共 4 条
[1]
GARCIA M, 1954, AM MATH MONTHLY, V61, P8
[2]
KANOLD HJ, 1956, MATH ANN, V132, P442
[3]
Laborde Pedro, 1955, AM MATH MONTHLY, V62, P348
[4]
ORE O, 1948, AM MATH MONTHLY, V55, P614