Voir la notice de l'article provenant de la source Novi sad journal of mathematics website
@article{NSJOM_1980_10_Nonea_17, author = {Bogdanovi\'c Stojan}, title = {r- semigrupe}, journal = {Novi Sad Journal of Mathematics}, pages = {149-152}, publisher = {mathdoc}, volume = {10}, year = {1980}, url = {http://geodesic.mathdoc.fr/item/NSJOM_1980_10_Nonea_17/} }
Bogdanović Stojan. r- semigrupe. Novi Sad Journal of Mathematics, Tome 10 (1980). http://geodesic.mathdoc.fr/item/NSJOM_1980_10_Nonea_17/