Kwan, Mei-ko (1960), "奇偶点图上作业法" , Acta Mathematica Sinica (in Chinese), 10: 263–266, MR 0162630.
Kwan, Mei-ko (1960), “奇偶点图上作业法” , Acta Mathematica Sinica (bằng tiếng Trung) 10: 263–266, MR 0162630 .