M. B. Heinemann, J. F. Garcia, C. M. Nunes, Z. M. M. Higa, S. A. Vasconcellos, and L. J. Richtzenhain, “Detection of Leptospira spp. from pure cultures and from experimentally contaminated bovine semen by polymerase chain reaction”, Braz. J. Vet. Res. Anim. Sci., vol. 36, no. 1, pp. 15–18, Jan. 1999, doi: 10.1590/S1413-95961999000100002.