Isong, I.K., Okhormhe, Z.A., Eze-Bassey, I., Okpokam, D.C. and Usoro, C.A.O. 2017. Levels of prolactin, progesterone, estradiol, luteinizing hormone and follicle stimulating hormone in infertile women in Calabar, Nigeria. International Journal of Reproduction, Contraception, Obstetrics and Gynecology. 5, 3 (Feb. 2017), 803–807. DOI:https://doi.org/10.18203/2320-1770.ijrcog20160588.