@article{DMGT_2013_33_2_a6,
     author = {Hammack, Richard H.},
     title = {Frucht{\textquoteright}s {Theorem} for the {Digraph} {Factorial}},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {329--336},
     publisher = {mathdoc},
     volume = {33},
     number = {2},
     year = {2013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_2013_33_2_a6/}
}