The microenvironment of the human antral follicle: interrelationships among the steroid levels in antral fluid, the population of granulosa cells, and the status of the oocyte in vivo and in vitro - McNatty,K.P.; Smith,D.M.; Makris,A.; Osathanondh,R.; Ryan,K.J. (J Clin Endocrinol Metab, 1979)