@article{GDZPPN002487926,
title = {On a General Associativity Law in Groupoids.},
journal = {Monatshefte f\"ur Mathematik},
volume = {114},
year = {1992},
pages = {51-58},
zbl = {0768.20032},
url = {http://dml.mathdoc.fr/item/GDZPPN002487926}
}
Niemenmaa, Markku; Kepka, Tomas. On a General Associativity Law in Groupoids.. Monatshefte für Mathematik, Tome 114 (1992) pp. 51-58. http://gdmltest.u-ga.fr/item/GDZPPN002487926/