On the connectivity ring of an abstract space

[1] CECH E, 1932, FUND MATH, V17, P149

[2] CECH E, ANNALS, P681

[3] The theory of topological commutative groups [J]. ANNALS OF MATHEMATICS, 1934, 35 : 361 - 388

[4] The higher connection of compact space and a class of connected transformations [J]. MATHEMATISCHE ANNALEN, 1927, 97 : 454 - 472

[5] 1935, P NAT ACAD, V21, P509

[1] CECH E, 1932, FUND MATH, V17, P149

[2] CECH E, ANNALS, P681

[3] The theory of topological commutative groups [J]. ANNALS OF MATHEMATICS, 1934, 35 : 361 - 388

[4] The higher connection of compact space and a class of connected transformations [J]. MATHEMATISCHE ANNALEN, 1927, 97 : 454 - 472

[5] 1935, P NAT ACAD, V21, P509