1. F. E. Goodwin, A. F. Skenazi and R. F. Lynch. Bulletin 80. September, 115 (1987).
2. J. L. Paaniez, Proceedings of the 141h International Galrani=ing Conference, Munich, Germany, p. GI. Zinc Development Ass. London (1985).
3. F. E. Goodwin, Proceedings of the 141h International Galraniling Conference, Munich, Germany, p. JI. Zinc Development Ass. London (1985).
4. A. F. Skenazi, Proceedings of the 141h International Galrani:ing Conference, Munich, Germany, p. OAI. Zinc Development Ass. London (1985).