@article{NSJOM_1991_21_1a_5,
     author = {Petri\'c Milenko V.},
     title = {Connectedness of the 

 generalized direct product of regular digraphs},
     journal = {Novi Sad Journal of Mathematics},
     pages = {57-64},
     publisher = {mathdoc},
     volume = {21},
     number = {1},
     year = {1991},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1991_21_1a_5/}
}