1. BEINEKE, L. W. and PIPPERT, R. C.,Recent advances in graph theory. Proc. Second Czecho-slovak Symposium, Prague 1974, 441-454. Academia, Prague 1975.
2. Beineke, L. W. andPippert, R. E.,On the enumeration of planar trees of hexagons. Glasgow Math. J.15 (1974), 131–147.
3. Brown, W. G.,Historical note on a recurrent combinatorial problem. Amer. Math. Monthly72 (1965), 973–977.
4. Comtet, L.,Analyse Combinatoire. Paris, Presses Universitaires de France, 1970, Volume 1.
5. Guy, R. K.,Dissecting a polygon into triangles. Bull. Malayan Math. Soc.5 (1968), 57–60.