diff --git a/PHPSkills/FactorGraphs/Factor.php b/PHPSkills/FactorGraphs/Factor.php
index 0ca2e46..2609b73 100644
--- a/PHPSkills/FactorGraphs/Factor.php
+++ b/PHPSkills/FactorGraphs/Factor.php
@@ -35,12 +35,14 @@ abstract class Factor
         return count($this->_messages);
     }
 
-    protected function &getVariables()
+    // DEBUG: make protected
+    public function &getVariables()
     {
         return $this->_variables;
     }
 
-    protected function &getMessages()
+    // DEBUG: make protected
+    public function &getMessages()
     {
         return $this->_messages;
     }
@@ -51,6 +53,11 @@ abstract class Factor
         Guard::argumentIsValidIndex($messageIndex, count($this->_messages), "messageIndex");
         $message = &$this->_messages[$messageIndex];
         $variable = &$this->_messageToVariableBinding->getValue($message);
+        // DEBUG
+        $selfName = (string)$this;
+        $debugName = (string)$variable;
+        $debugHash = \spl_object_hash($variable);
+        $debugValue = $variable->getValue();
         return $this->updateMessageVariable($message, $variable);
     }
 
@@ -86,9 +93,11 @@ abstract class Factor
     protected function &createVariableToMessageBindingWithMessage(Variable &$variable, Message &$message)
     {
         $index = count($this->_messages);
-        $this->_messages[] = &$message;
+        $localMessages = &$this->_messages;
+        $localMessages[] = &$message;
         $this->_messageToVariableBinding->setValue($message, $variable);
-        $this->_variables[] = &$variable;
+        $localVariables = &$this->_variables;
+        $localVariables[] = &$variable;
         return $message;
     }
 
diff --git a/PHPSkills/FactorGraphs/Message.php b/PHPSkills/FactorGraphs/Message.php
index 7d49e80..b2ba80a 100644
--- a/PHPSkills/FactorGraphs/Message.php
+++ b/PHPSkills/FactorGraphs/Message.php
@@ -20,6 +20,8 @@ class Message
 
     public function setValue(&$value)
     {
+        // DEBUG
+        $selfName = (string)$this;
         $this->_value = &$value;
     }
 
diff --git a/PHPSkills/FactorGraphs/Schedule.php b/PHPSkills/FactorGraphs/Schedule.php
index 34157d1..68450e4 100644
--- a/PHPSkills/FactorGraphs/Schedule.php
+++ b/PHPSkills/FactorGraphs/Schedule.php
@@ -34,7 +34,10 @@ class ScheduleStep extends Schedule
 
     public function visit($depth = -1, $maxDepth = 0)
     {
-        $delta = $this->_factor->updateMessageIndex($this->_index);
+        $currentFactor = &$this->_factor;
+        // DEBUG
+        $currentFactorName = (string)$currentFactor;
+        $delta = $currentFactor->updateMessageIndex($this->_index);
         return $delta;
     }
 }
diff --git a/PHPSkills/FactorGraphs/Variable.php b/PHPSkills/FactorGraphs/Variable.php
index a936916..9e5a2be 100644
--- a/PHPSkills/FactorGraphs/Variable.php
+++ b/PHPSkills/FactorGraphs/Variable.php
@@ -17,12 +17,18 @@ class Variable
     public function &getValue()
     {
         $value = &$this->_value;
+        // DEBUG
+        $selfHash = \spl_object_hash($this);
+        $selfName = (string)$this;
         return $value;
     }
 
     public function setValue(&$value)
     {
-        $this->_value = $value;
+        // DEBUG
+        $selfName = (string)$this;        
+        $selfHash = \spl_object_hash($this);
+        $this->_value = &$value;
     }
 
     public function resetToPrior()
@@ -57,15 +63,16 @@ class DefaultVariable extends Variable
 class KeyedVariable extends Variable
 {
     private $_key;
-    public function __construct($key, $name, &$prior)
+    public function __construct(&$key, $name, &$prior)
     {
         parent::__construct($name, $prior);
-        $this->_key = $key;
+        $this->_key = &$key;
     }
 
-    public function getKey()
+    public function &getKey()
     {
-        return $this->_key;
+        $key = &$this->_key;
+        return $key;
     }
 }
 
diff --git a/PHPSkills/HashMap.php b/PHPSkills/HashMap.php
index efc3153..db43bdf 100644
--- a/PHPSkills/HashMap.php
+++ b/PHPSkills/HashMap.php
@@ -7,29 +7,31 @@ class HashMap
     private $_hashToValue = array();
     private $_hashToKey = array();
 
-    public function &getValue($key)
+    public function &getValue(&$key)
     {
         $hash = self::getHash($key);
         $hashValue = &$this->_hashToValue[$hash];
         return $hashValue;
     }
 
-    public function setValue($key, $value)
+    public function setValue(&$key, &$value)
     {
         $hash = self::getHash($key);
-        $this->_hashToKey[$hash] = $key;
-        $this->_hashToValue[$hash] = $value;
+        $this->_hashToKey[$hash] = &$key;
+        $this->_hashToValue[$hash] = &$value;
         return $this;
     }
 
-    public function getAllKeys()
+    public function &getAllKeys()
     {
-        return \array_values($this->_hashToKey);
+        $keys = &\array_values($this->_hashToKey);
+        return $keys;
     }
 
     public function getAllValues()
     {
-        return \array_values($this->_hashToValue);
+        $values = &\array_values($this->_hashToValue);
+        return $values;
     }
 
     public function count()
@@ -37,7 +39,7 @@ class HashMap
         return \count($this->_hashToKey);
     }
 
-    private static function getHash($key)
+    private static function getHash(&$key)
     {
         if(\is_object($key))
         {
diff --git a/PHPSkills/RatingContainer.php b/PHPSkills/RatingContainer.php
index d1e06ff..6782910 100644
--- a/PHPSkills/RatingContainer.php
+++ b/PHPSkills/RatingContainer.php
@@ -2,6 +2,8 @@
 namespace Moserware\Skills;
 
 require_once(dirname(__FILE__) . "/HashMap.php");
+require_once(dirname(__FILE__) . "/Player.php");
+require_once(dirname(__FILE__) . "/Rating.php");
 
 class RatingContainer
 {
@@ -12,25 +14,27 @@ class RatingContainer
         $this->_playerToRating = new HashMap();
     }
 
-    public function &getRating($player)
+    public function &getRating(Player &$player)
     {
         $rating = &$this->_playerToRating->getValue($player);
         return $rating;
     }
 
-    public function setRating($player, $rating)
+    public function setRating(Player &$player, Rating $rating)
     {
         return $this->_playerToRating->setValue($player, $rating);
     }
     
-    public function getAllPlayers()
+    public function &getAllPlayers()
     {
-        return $this->_playerToRating->getAllKeys();
+        $allPlayers = &$this->_playerToRating->getAllKeys();
+        return $allPlayers;
     }
     
-    public function getAllRatings()
+    public function &getAllRatings()
     {
-        return $this->_playerToRating->getAllValues();
+        $allRatings = &$this->_playerToRating->getAllValues();
+        return $allRatings;
     }
 
     public function count()
diff --git a/PHPSkills/Team.php b/PHPSkills/Team.php
index c33343e..d818625 100644
--- a/PHPSkills/Team.php
+++ b/PHPSkills/Team.php
@@ -1,11 +1,13 @@
 <?php
 namespace Moserware\Skills;
 
+require_once(dirname(__FILE__) . '/Player.php');
+require_once(dirname(__FILE__) . '/Rating.php');
 require_once(dirname(__FILE__) . '/RatingContainer.php');
 
 class Team extends RatingContainer
 {
-    public function __construct(&$player = null, &$rating = null)
+    public function __construct(Player &$player = null, Rating &$rating = null)
     {
         parent::__construct();
         
@@ -15,12 +17,11 @@ class Team extends RatingContainer
         }
     }
 
-    public function addPlayer(&$player, &$rating)
+    public function addPlayer(Player &$player, Rating &$rating)
     {
         $this->setRating($player, $rating);
         return $this;
-    }
-    
+    }    
 }
 
 ?>
diff --git a/PHPSkills/Teams.php b/PHPSkills/Teams.php
index b55e8b5..35784ca 100644
--- a/PHPSkills/Teams.php
+++ b/PHPSkills/Teams.php
@@ -9,7 +9,8 @@ class Teams
         $result = array();
 
         foreach ($args as &$currentTeam) {
-            $result[] = $currentTeam;
+            $localCurrentTeam = &$currentTeam;
+            $result[] = $localCurrentTeam;
         }
 
         return $result;
diff --git a/PHPSkills/TrueSkill/FactorGraphTrueSkillCalculator.php b/PHPSkills/TrueSkill/FactorGraphTrueSkillCalculator.php
index b1833e1..55ddcbc 100644
--- a/PHPSkills/TrueSkill/FactorGraphTrueSkillCalculator.php
+++ b/PHPSkills/TrueSkill/FactorGraphTrueSkillCalculator.php
@@ -53,7 +53,10 @@ class FactorGraphTrueSkillCalculator extends SkillCalculator
         $factorGraph->buildGraph();
         $factorGraph->runSchedule();
 
-        $probabilityOfOutcome = $factorGraph->getProbabilityOfRanking();
+        $test = $factorGraph->getUpdatedRatings();
+
+        // DEBUG: Fix this :)
+        //$probabilityOfOutcome = $factorGraph->getProbabilityOfRanking();
 
         return $factorGraph->getUpdatedRatings();
     }
diff --git a/PHPSkills/TrueSkill/Factors/GaussianFactor.php b/PHPSkills/TrueSkill/Factors/GaussianFactor.php
index 62d1ed8..7f0fa7c 100644
--- a/PHPSkills/TrueSkill/Factors/GaussianFactor.php
+++ b/PHPSkills/TrueSkill/Factors/GaussianFactor.php
@@ -31,9 +31,10 @@ abstract class GaussianFactor extends Factor
 
     public function &createVariableToMessageBinding(Variable &$variable)
     {
+        $newDistribution = GaussianDistribution::fromPrecisionMean(0, 0);
         $binding = &parent::createVariableToMessageBindingWithMessage($variable,
                                                       new Message(
-                                                          GaussianDistribution::fromPrecisionMean(0, 0),
+                                                          $newDistribution,
                                                           sprintf("message from %s to %s", $this, $variable)));
         return $binding;
     }
diff --git a/PHPSkills/TrueSkill/Factors/GaussianLikelihoodFactor.php b/PHPSkills/TrueSkill/Factors/GaussianLikelihoodFactor.php
index f5982c7..7a97a21 100644
--- a/PHPSkills/TrueSkill/Factors/GaussianLikelihoodFactor.php
+++ b/PHPSkills/TrueSkill/Factors/GaussianLikelihoodFactor.php
@@ -39,9 +39,15 @@ class GaussianLikelihoodFactor extends GaussianFactor
     private function updateHelper(Message &$message1, Message &$message2,
                                   Variable &$variable1, Variable &$variable2)
     {
-        $message1Value = clone $message1->getValue();
-        $message2Value = clone $message2->getValue();
+        // DEBUG
+        $message1ValueTest = $message1->getValue();
+        $variable1ValueTest = $variable1->getValue();
+        $message2ValueTest = $message2->getValue();
+        $variable2ValueTest = $variable2->getValue();
 
+        $message1Value = clone $message1->getValue();
+        $message2Value = clone $message2->getValue();        
+        
         $marginal1 = clone $variable1->getValue();
         $marginal2 = clone $variable2->getValue();
 
@@ -67,7 +73,7 @@ class GaussianLikelihoodFactor extends GaussianFactor
     public function updateMessageIndex($messageIndex)
     {
         $messages = &$this->getMessages();
-        $vars = &$this->getVariables();
+        $vars = &$this->getVariables();       
 
         switch ($messageIndex)
         {
diff --git a/PHPSkills/TrueSkill/Factors/GaussianPriorFactor.php b/PHPSkills/TrueSkill/Factors/GaussianPriorFactor.php
index 8d38520..644ede7 100644
--- a/PHPSkills/TrueSkill/Factors/GaussianPriorFactor.php
+++ b/PHPSkills/TrueSkill/Factors/GaussianPriorFactor.php
@@ -39,7 +39,8 @@ class GaussianPriorFactor extends GaussianFactor
                 $oldMarginal->getPrecision() + $this->_newMessage->getPrecision() - $oldMessage->getValue()->getPrecision());
 
         $variable->setValue($newMarginal);
-        $message->setValue($this->_newMessage);
+        $newMessage = &$this->_newMessage;
+        $message->setValue($newMessage);
         return GaussianDistribution::subtract($oldMarginal, $newMarginal);
     }
 }
diff --git a/PHPSkills/TrueSkill/Factors/GaussianWeightedSumFactor.php b/PHPSkills/TrueSkill/Factors/GaussianWeightedSumFactor.php
index 62cd7ea..3278a6b 100644
--- a/PHPSkills/TrueSkill/Factors/GaussianWeightedSumFactor.php
+++ b/PHPSkills/TrueSkill/Factors/GaussianWeightedSumFactor.php
@@ -119,8 +119,13 @@ class GaussianWeightedSumFactor extends GaussianFactor
 
         foreach ($variablesToSum as &$currentVariable)
         {
-            $this->createVariableToMessageBinding($currentVariable);
+            $localCurrentVariable = &$currentVariable;
+            $this->createVariableToMessageBinding($localCurrentVariable);
         }
+
+        // DEBUG
+        $selfName = (string)$this;
+        $selfVars = &$this->getVariables();
     }
 
     public function getLogNormalization()
@@ -201,6 +206,8 @@ class GaussianWeightedSumFactor extends GaussianFactor
 
     public function updateMessageIndex($messageIndex)
     {
+        // DEBUG
+        $currentFactorName = (string)$this;
         $allMessages = &$this->getMessages();
         $allVariables = &$this->getVariables();
 
@@ -221,6 +228,12 @@ class GaussianWeightedSumFactor extends GaussianFactor
             $updatedVariables[] = &$allVariables[$indicesToUse[$i]];
         }
 
+        // DEBUG
+        foreach($allVariables as &$currentVariable)
+        {
+            $currentVarVal = &$currentVariable->getValue();
+        }
+
         return $this->updateHelper($this->_weights[$messageIndex],
                                    $this->_weightsSquared[$messageIndex],
                                    $updatedMessages,
diff --git a/PHPSkills/TrueSkill/Layers/IteratedTeamDifferencesInnerLayer.php b/PHPSkills/TrueSkill/Layers/IteratedTeamDifferencesInnerLayer.php
index 49eb424..39c5b94 100644
--- a/PHPSkills/TrueSkill/Layers/IteratedTeamDifferencesInnerLayer.php
+++ b/PHPSkills/TrueSkill/Layers/IteratedTeamDifferencesInnerLayer.php
@@ -83,14 +83,16 @@ class IteratedTeamDifferencesInnerLayer extends TrueSkillFactorGraphLayer
         $teamPerformancesToTeamPerformanceDifferencesLayerLocalFactors = &$this->_TeamPerformancesToTeamPerformanceDifferencesLayer->getLocalFactors();
         $teamDifferencesComparisonLayerLocalFactors = &$this->_TeamDifferencesComparisonLayer->getLocalFactors();
 
+        $firstPerfToTeamDiff = &$teamPerformancesToTeamPerformanceDifferencesLayerLocalFactors[0];
+        $firstTeamDiffComparison = &$teamDifferencesComparisonLayerLocalFactors[0];
         $itemsToSequence = array(
                     new ScheduleStep(
                         "send team perf to perf differences",
-                        &$teamPerformancesToTeamPerformanceDifferencesLayerLocalFactors[0],
+                        $firstPerfToTeamDiff,
                         0),
                     new ScheduleStep(
                         "send to greater than or within factor",
-                        &$teamDifferencesComparisonLayerLocalFactors[0],
+                        $firstTeamDiffComparison,
                         0)
                 );
 
@@ -110,18 +112,21 @@ class IteratedTeamDifferencesInnerLayer extends TrueSkillFactorGraphLayer
             $teamPerformancesToTeamPerformanceDifferencesLayerLocalFactors = &$this->_TeamPerformancesToTeamPerformanceDifferencesLayer->getLocalFactors();
             $teamDifferencesComparisonLayerLocalFactors = &$this->_TeamDifferencesComparisonLayer->getLocalFactors();
 
+            $currentTeamPerfToTeamPerfDiff = &$teamPerformancesToTeamPerformanceDifferencesLayerLocalFactors[$i];
+            $currentTeamDiffComparison = &$teamDifferencesComparisonLayerLocalFactors[$i];
+
             $currentForwardSchedulePiece =
                 $this->scheduleSequence(
                     array(
                             new ScheduleStep(
                                 sprintf("team perf to perf diff %d", $i),
-                                &$teamPerformancesToTeamPerformanceDifferencesLayerLocalFactors[$i], 0),
+                                $currentTeamPerfToTeamPerfDiff, 0),
                             new ScheduleStep(
                                 sprintf("greater than or within result factor %d", $i),
-                                &$teamDifferencesComparisonLayerLocalFactors[$i], 0),
+                                $currentTeamDiffComparison, 0),
                             new ScheduleStep(
                                 sprintf("team perf to perf diff factors [%d], 2", $i),
-                                &$teamPerformancesToTeamPerformanceDifferencesLayerLocalFactors[$i], 2)
+                                $currentTeamPerfToTeamPerfDiff, 2)
                         ), sprintf("current forward schedule piece %d", $i));
 
             $forwardScheduleList[] = $currentForwardSchedulePiece;
diff --git a/PHPSkills/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php b/PHPSkills/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
index b2757ed..4490f68 100644
--- a/PHPSkills/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
+++ b/PHPSkills/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
@@ -28,14 +28,16 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
         $inputVariablesGroups = &$this->getInputVariablesGroups();
         foreach ($inputVariablesGroups as &$currentTeam)
         {
-            $teamPerformance = &$this->createOutputVariable($currentTeam);
-            $newSumFactor = $this->createPlayerToTeamSumFactor($currentTeam, $teamPerformance);
+            $localCurrentTeam = &$currentTeam;
+            $teamPerformance = &$this->createOutputVariable($localCurrentTeam);
+            $newSumFactor = $this->createPlayerToTeamSumFactor($localCurrentTeam, $teamPerformance);
+            
             $this->addLayerFactor($newSumFactor);
 
             // REVIEW: Does it make sense to have groups of one?
             $outputVariablesGroups = &$this->getOutputVariablesGroups();
             $outputVariablesGroups[] = array($teamPerformance);
-        }
+        }        
     }
 
     public function createPriorSchedule()
@@ -58,7 +60,8 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
         $weights = array_map(
                         function($v)
                         {
-                            return PartialPlay::getPartialPlayPercentage($v->getKey());
+                            $player = &$v->getKey();
+                            return PartialPlay::getPartialPlayPercentage($player);
                         },
                         $teamMembers);
 
@@ -76,17 +79,18 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
         $localFactors = &$this->getLocalFactors();
         foreach($localFactors as &$currentFactor)
         {
-            $numberOfMessages = $currentFactor->getNumberOfMessages();
+            $localCurrentFactor = &$currentFactor;
+            $numberOfMessages = $localCurrentFactor->getNumberOfMessages();
             for($currentIteration = 1; $currentIteration < $numberOfMessages; $currentIteration++)
             {
                 $allFactors[] = new ScheduleStep("team sum perf @" . $currentIteration,
-                                                 $currentFactor, $currentIteration);
+                                                 $localCurrentFactor, $currentIteration);
             }
         }
         return $this->scheduleSequence($allFactors, "all of the team's sum iterations");
     }
 
-    private function createOutputVariable(&$team)
+    private function &createOutputVariable(&$team)
     {
         $memberNames = \array_map(function ($currentPlayer)
                                   {
@@ -95,7 +99,8 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
                                   $team);
 
         $teamMemberNames = \join(", ", $memberNames);
-        return $this->getParentFactorGraph()->getVariableFactory()->createBasicVariable("Team[" . $teamMemberNames . "]'s performance");
+        $outputVariable = &$this->getParentFactorGraph()->getVariableFactory()->createBasicVariable("Team[" . $teamMemberNames . "]'s performance");
+        return $outputVariable;
     }
 }
 
diff --git a/PHPSkills/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php b/PHPSkills/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
index 617cbe0..08487eb 100644
--- a/PHPSkills/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
+++ b/PHPSkills/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
@@ -24,7 +24,7 @@ class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
 {
     private $_teams;
 
-    public function __construct(TrueSkillFactorGraph &$parentGraph, &$teams)
+    public function __construct(TrueSkillFactorGraph &$parentGraph, array &$teams)
     {
         parent::__construct($parentGraph);
         $this->_teams = $teams;
@@ -35,14 +35,16 @@ class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
         $teams = &$this->_teams;
         foreach ($teams as &$currentTeam)
         {
+            $localCurrentTeam = &$currentTeam;
             $currentTeamSkills = array();
 
-            $currentTeamAllPlayers = &$currentTeam->getAllPlayers();
+            $currentTeamAllPlayers = $localCurrentTeam->getAllPlayers();
             foreach ($currentTeamAllPlayers as &$currentTeamPlayer)
             {
-                $currentTeamPlayerRating = $currentTeam->getRating($currentTeamPlayer);
-                $playerSkill = $this->createSkillOutputVariable($currentTeamPlayer);
-                $priorFactor = $this->createPriorFactor($currentTeamPlayer, $currentTeamPlayerRating, $playerSkill);
+                $localCurrentTeamPlayer = &$currentTeamPlayer;
+                $currentTeamPlayerRating = $currentTeam->getRating($localCurrentTeamPlayer);
+                $playerSkill = &$this->createSkillOutputVariable($localCurrentTeamPlayer);
+                $priorFactor = &$this->createPriorFactor($localCurrentTeamPlayer, $currentTeamPlayerRating, $playerSkill);
                 $this->addLayerFactor($priorFactor);
                 $currentTeamSkills[] = $playerSkill;
             }
@@ -73,11 +75,12 @@ class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
                                        $skillsVariable);
     }
 
-    private function createSkillOutputVariable($key)
+    private function &createSkillOutputVariable(&$key)
     {
         $parentFactorGraph = &$this->getParentFactorGraph();
         $variableFactory = &$parentFactorGraph->getVariableFactory();
-        return $variableFactory->createKeyedVariable($key, $key . "'s skill");
+        $skillOutputVariable = &$variableFactory->createKeyedVariable($key, $key . "'s skill");
+        return $skillOutputVariable;
     }
 }
 
diff --git a/PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php b/PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
index 8497e55..bd4df4f 100644
--- a/PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
+++ b/PHPSkills/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
@@ -31,9 +31,10 @@ class PlayerSkillsToPerformancesLayer extends TrueSkillFactorGraphLayer
 
             foreach ($currentTeam as &$playerSkillVariable)
             {
-                $currentPlayer = &$playerSkillVariable->getKey();
-                $playerPerformance = $this->createOutputVariable($currentPlayer);
-                $newLikelihoodFactor = $this->createLikelihood($playerSkillVariable, $playerPerformance);
+                $localPlayerSkillVariable = &$playerSkillVariable;
+                $currentPlayer = &$localPlayerSkillVariable->getKey();
+                $playerPerformance = &$this->createOutputVariable($currentPlayer);
+                $newLikelihoodFactor = $this->createLikelihood($localPlayerSkillVariable, $playerPerformance);
                 $this->addLayerFactor($newLikelihoodFactor);
                 $currentTeamPlayerPerformances[] = $playerPerformance;
             }            
@@ -47,9 +48,10 @@ class PlayerSkillsToPerformancesLayer extends TrueSkillFactorGraphLayer
         return new GaussianLikelihoodFactor(square($this->getParentFactorGraph()->getGameInfo()->getBeta()), $playerPerformance, $playerSkill);
     }
 
-    private function createOutputVariable(&$key)
+    private function &createOutputVariable(&$key)
     {
-        return $this->getParentFactorGraph()->getVariableFactory()->createKeyedVariable($key, $key . "'s performance");
+        $outputVariable = &$this->getParentFactorGraph()->getVariableFactory()->createKeyedVariable($key, $key . "'s performance");
+        return $outputVariable;
     }
 
     public function createPriorSchedule()
diff --git a/PHPSkills/TrueSkill/Layers/TeamPerformancesToTeamPerformanceDifferencesLayer.php b/PHPSkills/TrueSkill/Layers/TeamPerformancesToTeamPerformanceDifferencesLayer.php
index a5a6e38..a8a8405 100644
--- a/PHPSkills/TrueSkill/Layers/TeamPerformancesToTeamPerformanceDifferencesLayer.php
+++ b/PHPSkills/TrueSkill/Layers/TeamPerformancesToTeamPerformanceDifferencesLayer.php
@@ -46,9 +46,10 @@ class TeamPerformancesToTeamPerformanceDifferencesLayer extends TrueSkillFactorG
         return new GaussianWeightedSumFactor($output, $teams, $weights);
     }
 
-    private function createOutputVariable()
+    private function &createOutputVariable()
     {
-        return $this->getParentFactorGraph()->getVariableFactory()->createBasicVariable("Team performance difference");
+        $outputVariable = &$this->getParentFactorGraph()->getVariableFactory()->createBasicVariable("Team performance difference");
+        return $outputVariable;
     }
 }
 
diff --git a/PHPSkills/TrueSkill/TrueSkillFactorGraph.php b/PHPSkills/TrueSkill/TrueSkillFactorGraph.php
index 88f7340..3b79994 100644
--- a/PHPSkills/TrueSkill/TrueSkillFactorGraph.php
+++ b/PHPSkills/TrueSkill/TrueSkillFactorGraph.php
@@ -37,7 +37,7 @@ class TrueSkillFactorGraph extends FactorGraph
     private $_layers;
     private $_priorLayer;    
 
-    public function __construct(GameInfo &$gameInfo, &$teams, array $teamRanks)
+    public function __construct(GameInfo &$gameInfo, array &$teams, array $teamRanks)
     {
         $this->_priorLayer = new PlayerPriorValuesToSkillsLayer($this, $teams);
         $this->_gameInfo = $gameInfo;
@@ -98,7 +98,8 @@ class TrueSkillFactorGraph extends FactorGraph
             $localFactors = &$currentLayer->getLocalFactors();
             foreach ($localFactors as &$currentFactor)
             {
-                $factorList->addFactor($currentFactor);
+                $localCurrentFactor = &$currentFactor;
+                $factorList->addFactor($localCurrentFactor);
             }
         }
 
@@ -143,10 +144,12 @@ class TrueSkillFactorGraph extends FactorGraph
         {
             foreach ($currentTeam as &$currentPlayer)
             {
+                $localCurrentPlayer = &$currentPlayer->getKey();
+                $test = \spl_object_hash($localCurrentPlayer);
                 $newRating = new Rating($currentPlayer->getValue()->getMean(),
                                         $currentPlayer->getValue()->getStandardDeviation());
 
-                $result->setRating($currentPlayer, $newRating);
+                $result->setRating($localCurrentPlayer, $newRating);
             }
         }
 
diff --git a/PHPSkills/TrueSkill/TwoTeamTrueSkillCalculator.php b/PHPSkills/TrueSkill/TwoTeamTrueSkillCalculator.php
index cf742f4..ac1f598 100644
--- a/PHPSkills/TrueSkill/TwoTeamTrueSkillCalculator.php
+++ b/PHPSkills/TrueSkill/TwoTeamTrueSkillCalculator.php
@@ -146,9 +146,10 @@ class TwoTeamTrueSkillCalculator extends SkillCalculator
             $rankMultiplier = 1;
         }
 
-        foreach ($selfTeam->getAllPlayers() as $selfTeamCurrentPlayer)
+        foreach ($selfTeam->getAllPlayers() as &$selfTeamCurrentPlayer)
         {
-            $previousPlayerRating = $selfTeam->getRating($selfTeamCurrentPlayer);
+            $localSelfTeamCurrentPlayer = &$selfTeamCurrentPlayer;
+            $previousPlayerRating = $selfTeam->getRating($localSelfTeamCurrentPlayer);
 
             $meanMultiplier = (square($previousPlayerRating->getStandardDeviation()) + $tauSquared)/$c;
             $stdDevMultiplier = (square($previousPlayerRating->getStandardDeviation()) + $tauSquared)/square($c);
@@ -159,7 +160,7 @@ class TwoTeamTrueSkillCalculator extends SkillCalculator
             $newStdDev =
                 sqrt((square($previousPlayerRating->getStandardDeviation()) + $tauSquared)*(1 - $w*$stdDevMultiplier));
 
-            $newPlayerRatings->setRating($selfTeamCurrentPlayer, new Rating($newMean, $newStdDev));
+            $newPlayerRatings->setRating($localSelfTeamCurrentPlayer, new Rating($newMean, $newStdDev));
         }
     }
 
diff --git a/UnitTests/TrueSkill/FactorGraphTeamTrueSkillCalculatorTest.php b/UnitTests/TrueSkill/FactorGraphTeamTrueSkillCalculatorTest.php
index df278ac..3cee306 100644
--- a/UnitTests/TrueSkill/FactorGraphTeamTrueSkillCalculatorTest.php
+++ b/UnitTests/TrueSkill/FactorGraphTeamTrueSkillCalculatorTest.php
@@ -11,7 +11,7 @@ use Moserware\Skills\TrueSkill\FactorGraphTrueSkillCalculator;
 class FactorGraphTrueSkillCalculatorTest extends PHPUnit_Framework_TestCase
 {
     public function testFactorGraphTrueSkillCalculator()
-    {
+    {     
         $calculator = new FactorGraphTrueSkillCalculator();
         
         TrueSkillCalculatorTests::testAllTwoPlayerScenarios($this, $calculator);
diff --git a/UnitTests/TrueSkill/TrueSkillCalculatorTests.php b/UnitTests/TrueSkill/TrueSkillCalculatorTests.php
index 4f5d261..5280041 100644
--- a/UnitTests/TrueSkill/TrueSkillCalculatorTests.php
+++ b/UnitTests/TrueSkill/TrueSkillCalculatorTests.php
@@ -67,6 +67,8 @@ class TrueSkillCalculatorTests
     {
         $player1 = new Player(1);
         $player2 = new Player(2);
+        $p1Key = \spl_object_hash($player1);
+        $p2Key = \spl_object_hash($player2);
         $gameInfo = new GameInfo();
 
         $team1 = new Team($player1, $gameInfo->getDefaultRating());