1. Chan KW 1995 Migration controls and urban society in post-Mao China Seattle Population Research Center working paper, No. 95-2
2. Colby WH Crook FW Webb S-EH 1992 Agricultural statistics of the People's Republic of China, 1949–1990 Economic Research Service, United States Department of Agriculture. More recent data can be found at http://usda.mannlib.cornell.edu/