Shao, Xuemei. 1986. ?Long-Term Climatic Changes In Western Europe And East Asia?. Geology And Geography. Geology And Geography. University of Massachusetts.

Bradley, Raymond S. 1974. ?Secular Changes Of Precipitation In The Rocky Mountains And Adjacent Western States?. Geology And Geography. Geology And Geography. University of Boulder. http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=758390521&sid=2&Fmt=1&clientId=43922&RQT=309&VName=PQD.