diff --git a/ucoinpy/api/bma/tx/__init__.py b/ucoinpy/api/bma/tx/__init__.py
index a7adc5f37f58bdf0858e1128c47925e47a7a9e4a..384b7ff9f0b8827ae1ac2e400e1adc91efef2b48 100644
--- a/ucoinpy/api/bma/tx/__init__.py
+++ b/ucoinpy/api/bma/tx/__init__.py
@@ -38,6 +38,9 @@ class Process(Tx):
 
 class Sources(Tx):
     """Get transaction sources."""
+    def __init__(self, connection_handler, pubkey, module='tx'):
+        super(Tx, self).__init__(connection_handler, module)
+        self.pubkey = pubkey
 
     def __get__(self, **kwargs):
         assert self.pubkey is not None