FREE LOOPS AND NETS AND THEIR GENERALIZATIONS

[11] Group extensions and homology [J]. ANNALS OF MATHEMATICS, 1942, 43 : 757 - 831

[12] Projective planes [J]. TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY, 1943, 54 (1-3) : 229 - 277

[13] On free products of groups. [J]. MATHEMATISCHE ANNALEN, 1933, 108 : 26 - 36

[14] LEFSCHETZ S, 1942, AM MATH C PUBLICATIO, V27

[15] The Sub groups of Free groups. [J]. MATHEMATISCHE ZEITSCHRIFT, 1930, 32 : 315 - 318

[16] Levi Friedrich, 1936, COMPOS MATH, V3, P391

[17] On the immersion of an algebraic ring into a field. [J]. MATHEMATISCHE ANNALEN, 1937, 113 : 686 - 691

[18] Schreier O., 1927, ABH MATH SEM HAMBURG, V5, P161

[19] SMILEY MF, 1944, B AM MATH SOC, V50, P782

[20] TAKAHASI M, 1944, P IMP ACAD TOKYO, V20, P589

[11] Group extensions and homology [J]. ANNALS OF MATHEMATICS, 1942, 43 : 757 - 831

[12] Projective planes [J]. TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY, 1943, 54 (1-3) : 229 - 277

[13] On free products of groups. [J]. MATHEMATISCHE ANNALEN, 1933, 108 : 26 - 36

[14] LEFSCHETZ S, 1942, AM MATH C PUBLICATIO, V27

[15] The Sub groups of Free groups. [J]. MATHEMATISCHE ZEITSCHRIFT, 1930, 32 : 315 - 318

[16] Levi Friedrich, 1936, COMPOS MATH, V3, P391

[17] On the immersion of an algebraic ring into a field. [J]. MATHEMATISCHE ANNALEN, 1937, 113 : 686 - 691

[18] Schreier O., 1927, ABH MATH SEM HAMBURG, V5, P161

[19] SMILEY MF, 1944, B AM MATH SOC, V50, P782

[20] TAKAHASI M, 1944, P IMP ACAD TOKYO, V20, P589