共 5 条
[1]
Dehn M, 1912, MATH ANN, V71, P116
[2]
MAGNUS, 1931, MATH ANN, V105, P63
[3]
MAGNUS, 1930, J REINE ANGEW MATH, V163, P7
[4]
Reidemeister K., 1926, ABH MATH SEM HAMBURG, V5, P7, DOI DOI 10.1007/BF02952506
[5]
Schreier O., 1927, ABH MATH SEM HAMBURG, V5, P161