@article{GDZPPN002537095,
title = {Permutation group extension of groupoids.},
journal = {Publications de l'Institut Math\'ematique [Elektronische Ressource]},
volume = {35},
year = {1977},
pages = {255-258},
zbl = {0442.20044},
language = {en},
url = {http://dml.mathdoc.fr/item/GDZPPN002537095}
}
Sin-Min, L. Permutation group extension of groupoids.. Publications de l'Institut Mathématique [Elektronische Ressource], Tome 35 (1977) pp. 255-258. http://gdmltest.u-ga.fr/item/GDZPPN002537095/