Adefashola, Olamide R, et al. “Cervicovaginal Fluid Beta Human Chorionic Gonadotropin Assay As an Early Predictor of Spontaneous Preterm Delivery Among Antenatal Patients”. The Nigerian Health Journal, vol. 21, no. 2, July 2021, pp. 45-59, https://tnhjph.com/index.php/tnhj/article/view/523.