共 6 条
[4]
Hartmanis J., 1966, ALGEBRAIC STRUCTURE
[5]
Oystein Ore, 1942, DUKE MATH J, V9, P573, DOI [DOI 10.1215/S0012-7094-42-00942-6, 10.1215/S0012-7094-42-00942-6]
[6]
SCHUTT D, 1968, ZAMM, V48, pT124