1. Secondary structure of single-stranded nucleic acids;Waterman;Advances in Mathematics Supplementary Studies,1978
2. J.A. Howell, T.F. Smith and M.S. Waterman, Computation of generating functions for biological molecules, Los Alamos preprint LA-UR 78-1419.
3. A Handbook of Integer Sequences;Sloane,1973
4. Motzkin numbers;Donaghey;J. Combinatorial Theory,1977
5. Combinatorial Identities;Riordan,1968