Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MAT_1962_6_1_a0, author = {D. Kan}, title = {A combinatorial definition of homotopy groups}, journal = {Matematika}, pages = {3--32}, publisher = {mathdoc}, volume = {6}, number = {1}, year = {1962}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MAT_1962_6_1_a0/} }
D. Kan. A combinatorial definition of homotopy groups. Matematika, Tome 6 (1962) no. 1, pp. 3-32. http://geodesic.mathdoc.fr/item/MAT_1962_6_1_a0/