Viana, C. H. C.; Arruda, R. P. de; Moretti, A. S.; Visintin, J. A. Ovarian Cysts, Rectal Palpation and Ultra-Rectal Ultra- Sonography Diagnosis in Sows: Literature Review and Two Clinical Report Studies. Braz. J. Vet. Res. Anim. Sci. 1998, 35 (2), 64-68. https://doi.org/10.1590/S1413-95961998000200003.