KAUSHAL, GAGANDEEP, et al. “A Comparative Study on Sperm Penetration in Estrual Mucus and Polyacrylamide Gel in Relation to Seminal Characteristics”. The Indian Journal of Animal Reproduction, vol. 25, no. 2, Mar. 2023, pp. 151-3, https://acspublisher.com/journals/index.php/ijar/article/view/6340.