城垣 = Chengyuan Cheng yuan = Chengyuan韩扬主编, Bei Jing Shi Gu Dai Jian Zhu Yan Jiu Suo Bian & 3 more2014PDF
中华成语词典 = Zhonghua chengyu cidian: Zhonghua chengyu cidian中华书局编辑部编, Zhong hua shu ju bian ji bu. bian ji bu & 2 more2004PDF