@article{NSJOM_1982_12_Nonea_30,
     author = {Stojakovi\'c Zoran},
     title = {On bisymmetric [n,m]- 

 groupoids},
     journal = {Novi Sad Journal of Mathematics},
     pages = {399-405},
     publisher = {mathdoc},
     volume = {12},
     year = {1982},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1982_12_Nonea_30/}
}