1. Personal communication;Ingraham,1976
2. Prevalence and Types of Uterine Microflora;Heist,1974
3. Diagnostic Procedures in Veterinary Microbiology;Carter,1973
4. Statistical Methods;Snedecor,1971
5. Association of Pelvic Inflammatory Disease with the Intrauterine Device;Mishell;Clin. Obstet. and Gynec.,1969