@article{NSJOM_2005_35_2a_12,
     author = {J. U\v{s}an},
     title = {A comment on $(n,m)-$groups},
     journal = {Novi Sad Journal of Mathematics},
     pages = {133-141},
     publisher = {mathdoc},
     volume = {35},
     number = {2},
     year = {2005},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_2005_35_2a_12/}
}