Harary, Frank Four difficult unsolved problems in graph theory. (English) Zbl 0329.05125 Recent Adv. Graph Theory, Proc. Symp. Prague 1974, 249-256 (1975). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 4 Documents MSC: 05Cxx Graph theory 05C15 Coloring of graphs and hypergraphs 05C99 Graph theory 05C30 Enumeration in graph theory PDFBibTeX XML