1. Split graphs;Földes,1977
2. Combinatorial relations and chromatic graphs;Gleason;Can. J. Math.,1955
3. Algorithmic Graph Theory and Perfect Graphs;Golumbic,1980
4. Ramsey Theory;Graham,1980
5. A Helly Type problem in Trees;Gyárfás;Coll. Math. Soc. J. Bolyai,1969