[1] S. A. BURR P. ERDÖS L. LOVÁSZ:
On graphs of Ramsey type. Ars Combin. 1 (1976), 167-190.
MR 0419285
[2] L. LOVÁSZ:
Combinatorial problems and exercises. Akadémiai Kiadó, Budapest 1979, 9. 18.
MR 0537284
[3] S. POLJAK V. RÖDL:
On the Arc-chromatic number of a digraph. J. Comb. Theory Ser. B 31 (1981), 190-198.
MR 0630982