@article{DMGT_2003_23_2_a8,
     author = {Nesetril, Jaroslav and Tardif, Claude},
     title = {On maximal finite antichains in the homomorphism order of directed graphs},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {325--332},
     publisher = {mathdoc},
     volume = {23},
     number = {2},
     year = {2003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_2003_23_2_a8/}
}