A. Vince Steve Wilson Dyck's map (3, 7)<sub>8</sub> is a counterexample to a clique covering conjecture. 157-160 1992 54 J. Comb. Theory, Ser. B 1 http://dx.doi.org/10.1016/0095-8956(92)90074-8 db/journals/jct/jctb54.html#VinceW92