diff --git a/handler.inc b/handler.inc
index 11e18e9..73d69af 100644
--- a/handler.inc
+++ b/handler.inc
@@ -32,6 +32,32 @@ class CerException extends Exception {
 
 }
 
+/**
+ * Exception thrown in case of attempted reference overloading.
+ */
+class CerReferenceOverloadingException extends CerException {
+
+  /**
+   * @constructor
+   *
+   * @param array $instance
+   *  Field instance info array, i.e., returned by field_info_instance().
+   */
+  public function __construct($instance) {
+    $field = isset($instance['field']) ? $instance['field'] : field_info_field($instance['field_name']);
+
+    $variables = array(
+      '@field' => $instance['field_name'],
+      '@entity_type' => $instance['entity_type'],
+      '@bundle' => $instance['bundle'],
+      '!cardinality' => $field['cardinality'],
+    );
+
+    parent::__construct('Could not add reference in @field on @entity_type of type @bundle (maximum !cardinality values).', $variables);
+  }
+
+}
+
 interface CerHandlerInterface {
 
   /**
@@ -327,7 +353,7 @@ class CerHandler extends CerHandlerBase implements CerHandlerInterface {
       throw new CerException('Cannot create duplicate reference from remote entity.');
     }
     elseif ($this->filled($this->getRemoteReferenceIDs($entity), $this->remote['field'])) {
-      throw new CerException('Remote field cannot support any more references.');
+      throw new CerReferenceOverloadingException($this->remote);
     }
     else {
       $languages = field_available_languages($this->remote['entity_type'], $this->remote['field']);
@@ -352,7 +378,7 @@ class CerHandler extends CerHandlerBase implements CerHandlerInterface {
       throw new CerException('Cannot create duplicate reference to remote entity.');
     }
     elseif ($this->filled($this->getLocalReferenceIDs(), $this->local['field'])) {
-      throw new CerException('Local field cannot support any more references.');
+      throw new CerReferenceOverloadingException($this->local);
     }
     else {
       $languages = field_available_languages($this->local['entity_type'], $this->local['field']);