diff --git a/accountant/api/views/entries.py b/accountant/api/views/entries.py
index 7b1b997..f2c41d9 100644
--- a/accountant/api/views/entries.py
+++ b/accountant/api/views/entries.py
@@ -84,7 +84,7 @@ class OperationListResource(Resource):
 
         session.add(operation)
 
-        return Operation.query(session).get(operation.id)
+        return operation
 
 
 class OperationResource(Resource):
@@ -94,7 +94,7 @@ class OperationResource(Resource):
         """
         Get operation.
         """
-        operation = Operation.query(session).get(operation_id)
+        operation = session.query(Operation).get(operation_id)
 
         if not operation:
             return None, 404
@@ -109,7 +109,7 @@ class OperationResource(Resource):
         assert (id not in kwargs or kwargs.id is None
                 or kwargs.id == operation_id)
 
-        operation = Operation.query(session).get(operation_id)
+        operation = session.query(Operation).get(operation_id)
 
         if not operation:
             return None, 404
@@ -125,7 +125,7 @@ class OperationResource(Resource):
     @session_aware
     @marshal_with_field(Object(resource_fields))
     def delete(self, operation_id, session):
-        operation = Operation.query(session).get(operation_id)
+        operation = session.query(Operation).get(operation_id)
 
         if not operation:
             return None, 404