@article{01868897, title = {Free groupoids with axioms of the form }, journal = {Novi Sad Journal of Mathematics}, volume = {29}, year = {1999}, pages = {131-147}, zbl = {1011.20064}, language = {en}, url = {http://dml.mathdoc.fr/item/01868897} }
Čupona, Ǵorǵi; Celakoski, Naum; Janeva, Biljana. Free groupoids with axioms of the form . Novi Sad Journal of Mathematics, Tome 29 (1999) pp. 131-147. http://gdmltest.u-ga.fr/item/01868897/