@article{02116312,
title = {Special morphisms of groupoids.},
journal = {Novi Sad Journal of Mathematics},
volume = {32},
year = {2002},
pages = {23-36},
zbl = {1053.20048},
language = {en},
url = {http://dml.mathdoc.fr/item/02116312}
}
Ivan, Gheorghe. Special morphisms of groupoids.. Novi Sad Journal of Mathematics, Tome 32 (2002) pp. 23-36. http://gdmltest.u-ga.fr/item/02116312/