diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index b57f93b6..ba505fb5 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -877,7 +877,7 @@ class ReferenceField(BaseField):
             content = StringField()
             foo = ReferenceField('Foo')
 
-        Bar.register_delete_rule(Foo, 'bar', NULLIFY)
+        Bar.register_delete_rule(Foo, 'foo', NULLIFY)
 
     .. note ::
         `reverse_delete_rule` does not trigger pre / post delete signals to be
@@ -1013,7 +1013,7 @@ class ReferenceField(BaseField):
 class CachedReferenceField(BaseField):
     """
     A referencefield with cache fields to purpose pseudo-joins
-    
+
     .. versionadded:: 0.9
     """
 
@@ -1707,17 +1707,17 @@ class SequenceField(BaseField):
     :param collection_name:  Name of the counter collection (default 'mongoengine.counters')
     :param sequence_name: Name of the sequence in the collection (default 'ClassName.counter')
     :param value_decorator: Any callable to use as a counter (default int)
-        
+
     Use any callable as `value_decorator` to transform calculated counter into
     any value suitable for your needs, e.g. string or hexadecimal
     representation of the default integer counter value.
-    
+
     .. note::
-    
-        In case the counter is defined in the abstract document, it will be 
-        common to all inherited documents and the default sequence name will 
+
+        In case the counter is defined in the abstract document, it will be
+        common to all inherited documents and the default sequence name will
         be the class name of the abstract document.
-    
+
     .. versionadded:: 0.5
     .. versionchanged:: 0.8 added `value_decorator`
     """