Voir la notice de l'article provenant de la source Novi sad journal of mathematics website
@article{NSJOM_1978_8_Nonea_7, author = {U\v{s}an Janez and Stojakovi\'c Zoran}, title = {Orthogonal systems of partial operations}, journal = {Novi Sad Journal of Mathematics}, pages = {47-51}, publisher = {mathdoc}, volume = {8}, year = {1978}, url = {http://geodesic.mathdoc.fr/item/NSJOM_1978_8_Nonea_7/} }
Ušan Janez; Stojaković Zoran. Orthogonal systems of partial operations. Novi Sad Journal of Mathematics, Tome 8 (1978). http://geodesic.mathdoc.fr/item/NSJOM_1978_8_Nonea_7/