A prospective randomized study on oestradiol valerate supplementation in addition to intravaginal micronized progesterone in buserelin and HMG induced superovulation. - Smitz,J.; Bourgain,C.; Van Waesgerghe,L.; Camus,M.; Devroey,P.; Van Steirteghem,A.C. (Hum Reprod, 1993)