1. Ugwuja, E., Ugwu, N.C., & Ejikeme, B.N. (2008). Prevalence of low sperm count and abnormal semen parameters in male partners of women consulting at infertility clinic in Abakaliki, Nigeria. African Journal of Reproductive Health, 12 (1), 67-73. Retrieved from: https://www.ajrh.info/index.php/ajrh/issue/view/AJRH%202008%201
2. Schmidt, L., Minister, K., & Helm, P. (1995). Infertility and the seeking of infertility treatment in a representative population. British Journal of Obstetrics and Gynaecology, 102, 978-984.
3. Larsen, U. (2000). Primary and secondary infertility in sub-Saharan Africa. International Journal of Epidemiology, 29 (2), 285-291. doi: 10.1093/ije/29.2.285.
4. Agarwal, A., Mulgund, A., Hamada, A., & Chyatte, M. R. (2015). A unique view on male infertility around the globe. Reproductive Biology and Endocrinology, 13, 37. doi: 10.1186/s12958-015-0032-1.
5. Iatskiv, O., & Tarnovska, А. (2012). Prychyny i formy cholovichoho nepliddia ta metody diahnostyky eiakuliatu yak osnovnoho pokaznyka cholovichoho zdorovia [Causes and forms of male infertility and methods of diagnosis ejaculate, as the main indicator of male health]. Visnyk Lvivskoho universytetu. Seriia biolohichna – Visnyk of the Lviv University. Series Biology, 60, 4-20.