1. G.W. Duncan and D.R. Kalkwarf, in: “Human Reproduction: Conception and Contraception,” E.S.E. Hafez and T.N. Evans, eds., Harper and Row, New York, (1975). pp. 483–503.
2. H.L. Gabelnick, ed., “Drug Delivery Systems,” Workshop Sponsored by NICHD, Bethesda, Maryland, August 2–3, (1976).
3. D.R. Cowsar, in: “Controlled Release of Biologically Active Agents,” A.C. Tanquary and R.E. Lacey, eds., Plenum Press, New York, (1974). pp. 1–13.
4. L.R. Beck, D.R. Cowsar, and V.Z. Pope, Research Frontiers in Fertility Regulation 1 (1): 1 (1980).
5. J. Newton and J. McEwan, Fertil. Contracept. 1: 35 (1977).