共 4 条
[1]
Andre J., 1954, MATH Z, V60, P156
[3]
FINITE NETS, .1. NUMERICAL INVARIANTS
[J].
CANADIAN JOURNAL OF MATHEMATICS-JOURNAL CANADIEN DE MATHEMATIQUES,
1951, 3 (01)
:94-107
[4]
Ostrom T. G., 1964, T AM MATH SOC, V111, P1