Joya, F. R.; Ortiz, J. D. G.; Bandala, C. R.; Gutierrez, M. de la P.; Sosa, M. I. T.; Vilchis, A. B. Association of Cortisol Serum Levels As a Prognostic Factor in Threat of Pre-Term Birth. Int J Reprod Contracept Obstet Gynecol 2021, 10, 825-829.