@article{BMMS_2000_23_1_a8,
     author = {Hazrul Iswadi and Edy Tri Baskoro},
     title = {On
                        (4,2)-digraphs {Containing} a {Cycle} of {Length} 2},
     journal = {Bulletin of the Malaysian Mathematical Society},
     year = {2000},
     volume = {23},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/BMMS_2000_23_1_a8/}
}