1. K.A. Baker, P.C. Fishburn and F.S. Roberts, Partial orders of dimension 2, internal orders, and internal graphs, Rand Corporation Publication P-4376.
2. Maximal dimensional partially ordered sets I, Hiraguchi's theorem;Bogart;Discrete Math.,1973
3. A decomposition theorem for partially ordered sets;Dilworth;Ann. of Math.,1950
4. Partially ordered sets;Dushnik;Am. J. Math.,1940
5. Caractérisation des graphs nonorrentés dont on peut??rienter les arêtes de manière à obtenir le graphe d'une relatim d'ordre;Ghouila-Houri;C.R. Acad. Sci. Paris Sér. A–B,1962