by Felix Klein ; translated by M. Ackerman. by Sigmund Freud ; translated by A. A. Brill. by Luo Hanxian ; translated by Wang Huimin. by Ervin Szèucs ; [translated by B. Balkay]. by R. Courant ; translated by E.J. McShane. by Liu Lili ; translated by Zhong Jiangtao. Robert Fricke, Felix Klein ; translated by Arthur M. Dupre Wilhelm Klingenberg ; translated by David Hoffman. by Qiu Haiping ; translated by Jiang Xiaoli.