diff --git a/src/DataObjects/WorkflowDefinition.php b/src/DataObjects/WorkflowDefinition.php
index 58d58bb1..3c10baac 100644
--- a/src/DataObjects/WorkflowDefinition.php
+++ b/src/DataObjects/WorkflowDefinition.php
@@ -473,7 +473,7 @@ public function incomingTitle()
         } elseif (isset($req['Title']) && !empty($req['Title'])) {
             $incomingTitle = $req['Title'];
         } else {
-            $incomingTitle = self::$default_workflow_title_base;
+            $incomingTitle = WorkflowDefinition::$default_workflow_title_base;
         }
         return $incomingTitle;
     }
diff --git a/src/DataObjects/WorkflowTransition.php b/src/DataObjects/WorkflowTransition.php
index 56acdd73..a8116942 100644
--- a/src/DataObjects/WorkflowTransition.php
+++ b/src/DataObjects/WorkflowTransition.php
@@ -282,19 +282,19 @@ public function extendedRequiredFieldsNotSame($data = null)
         $check = array('ActionID','NextActionID');
         foreach ($check as $fieldName) {
             if (!isset($data[$fieldName])) {
-                return self::$extendedMethodReturn;
+                return WorkflowTransition::$extendedMethodReturn;
             }
         }
         // Have we found some identical values?
         if ($data[$check[0]] == $data[$check[1]]) {
             // Used to display to the user, so the first of the array is fine
-            self::$extendedMethodReturn['fieldName'] = $check[0];
-            self::$extendedMethodReturn['fieldValid'] = false;
-            self::$extendedMethodReturn['fieldMsg'] = _t(
+            WorkflowTransition::$extendedMethodReturn['fieldName'] = $check[0];
+            WorkflowTransition::$extendedMethodReturn['fieldValid'] = false;
+            WorkflowTransition::$extendedMethodReturn['fieldMsg'] = _t(
                 'WorkflowTransition.TRANSITIONLOOP',
                 'A transition cannot lead back to its parent action.'
             );
         }
-        return self::$extendedMethodReturn;
+        return WorkflowTransition::$extendedMethodReturn;
     }
 }
diff --git a/src/Forms/AWRequiredFields.php b/src/Forms/AWRequiredFields.php
index 44ca7c57..903a8ad1 100644
--- a/src/Forms/AWRequiredFields.php
+++ b/src/Forms/AWRequiredFields.php
@@ -105,11 +105,11 @@ protected function getData()
 
     public function setCaller($caller)
     {
-        self::$caller = $caller;
+        AWRequiredFields::$caller = $caller;
     }
 
     public function getCaller()
     {
-        return self::$caller;
+        return AWRequiredFields::$caller;
     }
 }
diff --git a/src/Jobs/WorkflowReminderJob.php b/src/Jobs/WorkflowReminderJob.php
index 8c863f96..89739fae 100644
--- a/src/Jobs/WorkflowReminderJob.php
+++ b/src/Jobs/WorkflowReminderJob.php
@@ -31,7 +31,7 @@ class WorkflowReminderJob extends AbstractQueuedJob
     public function __construct($repeatInterval = 0)
     {
         if (!$this->repeatInterval) {
-            $this->repeatInterval = $repeatInterval ? $repeatInterval : self::DEFAULT_REPEAT;
+            $this->repeatInterval = $repeatInterval ? $repeatInterval : WorkflowReminderJob::DEFAULT_REPEAT;
             $this->totalSteps = 2;
             $this->currentStep = 1;
         }