Voir la notice de l'article provenant de la source eLibrary of Mathematical Institute of the Serbian Academy of Sciences and Arts
@article{PIM_1979_N_S_26_40_a34, author = {Zoran Stojakovi\'c and Janez U\v{s}an}, title = {On {\ensuremath{\pi}-Groupoids}}, journal = {Publications de l'Institut Math\'ematique}, pages = {283 }, publisher = {mathdoc}, volume = {_N_S_26}, number = {40}, year = {1979}, url = {http://geodesic.mathdoc.fr/item/PIM_1979_N_S_26_40_a34/} }
Zoran Stojaković; Janez Ušan. On π-Groupoids. Publications de l'Institut Mathématique, _N_S_26 (1979) no. 40, p. 283 . http://geodesic.mathdoc.fr/item/PIM_1979_N_S_26_40_a34/