1 Liu, Xia. Yan, Sheng. Zhongguo qing nian dang dang shi ji zheng gang / bian zhu zhe Liu Xia, Yan Sheng Washinton, D.C. : 1975 Center for Chinese Materials, Association of Research Libraries ca. 45 leaves ; Colophon title. Photocopy. Each leaf represents 2 pages of the original.