Kao; Fang; Sah, Science Reports of National Tsing Hua University, Series A: Mathematical, Physical, and Engineering Sciences, 1936, vol. 3, p. 109,110,111
Kao; Fang; Sah, Science Reports of National Tsing Hua University, Series A: Mathematical, Physical, and Engineering Sciences, 1936, vol. 3, p. 109,110,111