http://www.centralnation.com/1952-PRC.html

The outer mongolia in "ROC" is not equal to "PRC"

under PRC , outer Mongolia is larger.

USSR pushed ccp to yield borders to Outer Mongolia and Outer Mongolia

yielded to USSR 1950s. The result "PRC" lost more lands to "PRM"-- Outer Mongolia,

Part of these called east mongolia, another part called west mongolia,

West mongolia, KMT troops used force to control 1946,

Under ROC, Tan area is considered to be a part of China, although USSR invaded

PRC gave out