(2) China Forms Its First Carrier Escort Group. Strategy Page, Apr 23, 2013 http://strategypage.com/htmw/htsurf/articles/20130423.aspx
(paragraph 1: "The escort group for China’s first aircraft carrier (the Liaoning) is being formed. It currently consists of two Type 051C destroyers and two Type 054A frigates plus a supply ship. It is similar to what the U.S. has long used, which is currently 3-4 destroyers, 1-2 frigates, an SSN (nuclear submarine), and a supply ship. Chinese SSNs are few and not very good, which is why China probably has not assigned one to their escort group")