1. On the possibilities of π-ylides
2. Heterocyclic mesomeric betaines
3. Chemical Graph Theory, Vol. 2, pp. 1-26. CRC Press, Boca Raton, FL (1983).
4. Program 455. Quantum Chemistry Program Exchange, Bloomington, IN, 1991.
5. and Program 446. Quantum Chemistry Program Exchange, Bloomington, IN, 1991.