diff --git a/HISTORY.rst b/HISTORY.rst
index 072ec6a..cff4ca7 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -3,6 +3,16 @@
 History
 -------
 
+0.3.3 (2017-06-15)
+~~~~~~~~~~~~~~~~~~
+
+* Fixed bug which did not allow to use SQLAlchemy backend fully
+  without having ``django.contrib.contenttypes`` in installed apps.
+  See `#36 <https://github.com/miki725/django-url-filter/issues/36>`_.
+* Improved SQLAlchemy versions compatibility.
+* Added ``URLFilterBackend`` alias in DRF integration for backend to reduce
+  confusion with ``DjangoFilterBackend`` as in url filter core backend.
+
 0.3.2 (2017-05-19)
 ~~~~~~~~~~~~~~~~~~
 
diff --git a/url_filter/__init__.py b/url_filter/__init__.py
index a725b33..7762f3f 100644
--- a/url_filter/__init__.py
+++ b/url_filter/__init__.py
@@ -4,4 +4,4 @@
 
 __author__ = 'Miroslav Shubernetskiy'
 __email__ = 'miroslav@miki725.com'
-__version__ = '0.3.2'
+__version__ = '0.3.3'
diff --git a/url_filter/backends/sqlalchemy.py b/url_filter/backends/sqlalchemy.py
index 09c3a82..39a94ba 100644
--- a/url_filter/backends/sqlalchemy.py
+++ b/url_filter/backends/sqlalchemy.py
@@ -66,7 +66,7 @@ def get_model(self):
         """
         Get the model from the given queryset
         """
-        return self.queryset._primary_entity.entities[0]
+        return self.queryset._only_entity_zero().mapper.class_
 
     def filter_by_specs(self, queryset):
         """
diff --git a/url_filter/filtersets/django.py b/url_filter/filtersets/django.py
index 1f8421b..df4c5f2 100644
--- a/url_filter/filtersets/django.py
+++ b/url_filter/filtersets/django.py
@@ -3,7 +3,7 @@
 import operator
 
 from django import forms
-from django.contrib.contenttypes.fields import GenericForeignKey
+from django.conf import settings
 from django.db import models
 from django.db.models.fields.related import ForeignObjectRel, RelatedField
 
@@ -16,6 +16,13 @@
 __all__ = ['ModelFilterSet', 'DjangoModelFilterSetOptions']
 
 
+GenericForeignKey = None
+
+
+if 'django.contrib.contenttypes' in settings.INSTALLED_APPS:
+    from django.contrib.contenttypes.fields import GenericForeignKey
+
+
 MODEL_FIELD_OVERWRITES = SubClassDict({
     models.AutoField: forms.IntegerField(min_value=0),
     models.FileField: lambda m: forms.CharField(max_length=m.max_length),
@@ -95,7 +102,7 @@ def _build_filter(self, name, state):
                 raise SkipFilter
             return self._build_filterset_from_reverse_field(field)
 
-        elif isinstance(field, GenericForeignKey):
+        elif GenericForeignKey and isinstance(field, GenericForeignKey):
             raise SkipFilter
 
         else:
diff --git a/url_filter/integrations/drf.py b/url_filter/integrations/drf.py
index d65e868..3957fc5 100644
--- a/url_filter/integrations/drf.py
+++ b/url_filter/integrations/drf.py
@@ -162,3 +162,6 @@ def filter_queryset(self, request, queryset, view):
                 raise ValidationError(e.message_dict)
 
         return queryset
+
+
+URLFilterBackend = DjangoFilterBackend