@article{DMGT_1999_19_2_a13,
     author = {Skupie\'n, Zdzis{\l}aw},
     title = {Problems on fully irregular digraphs},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {253--255},
     publisher = {mathdoc},
     volume = {19},
     number = {2},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_1999_19_2_a13/}
}