1. Suppression of fertility by intrauterine copper and zinc in rabbits;Zipper;Am. J. Obst. Gynec.,1969
2. Human fertility control through the use of endouterine metal antagonisms of trace elements (EMATE);Zipper,1970
3. Biological action of copper. Development of a new type of intrauterine contraception, Cu-7;Zipper,1972
4. Factors that limit the efficiency of copper-carrying IUDs;Zipper,1973
5. Clinical studies with Cu7: a comparison of results in parous and nulliparous women;Stewart,1972