NAKHASHl, H C, et al. “COMPARATIVE EFFICACY OF PROGESTERONE ASSAY AND ULTRASONOGRAPHY FOR EARLY PREGNANCY DIAGNOSIS IN BUFFALOES”. The Indian Journal of Animal Reproduction, vol. 31, no. 1, Jan. 2023, pp. 20-23, https://acspublisher.com/journals/index.php/ijar/article/view/4520.