where are the long distance bus stations in Nanjing?

There are several long-distance bus stations in that city such as Zhongyangmen Long-distance Bus Station, South Long-distance Bus Station, East Long-distance Bus Station, North Bus Station and Jiangning Bus Station. So which one do you refer to?
The busiest bus station is the Zhongyangmen Bus Station at No. 1, Jianning Road, near to local railway station.

Thank you. The names make it possible to locate them with mapquest and hopefully determine which one my Jiangdu bus visits.