1. Problem 3674;Birkhoff;Am. Math. Monthly,1934
2. On the partitions of a polygon;Cayley;Proc. London Math. Soc.,1891
3. Extrapolation when little is known;Fine;Information and Control,1970
4. Research bibliography of two special number sequences;Gould;Mathematica Monongaliae,1971
5. Note on the number of pairs of nonintersecting routes;Levine;Scripta Math.,1959