@article{DMGT_2012_32_1_a12,
     author = {Hailat, Mohammad},
     title = {On a generalization of the friendship theorem},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {153--160},
     publisher = {mathdoc},
     volume = {32},
     number = {1},
     year = {2012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_2012_32_1_a12/}
}