Xu Xing of the Chinese Institute of Vertebrate Paleontology and Paleoanthropology ( IVPP ) in Beijing , along with Peter Makovicky , formerly of the American Museum of Natural History ( AMNH ) in New York City and others , published a cladistic analysis in the 2002 description of Liaoceratops . This analysis is very similar to one published by Makovicky in 2001 . Makovicky , who currently work at the Field Museum of Natural History in Chicago , also included this analysis in his 2002 doctoral thesis . Xu and other colleagues added Yinlong to this analysis in 2006 .