Wikse, S. E., G. M. Rogers, S. Ramachandran, T. J. Engelken, W. B. Epperson, R. L. Larson, J. Maas, E. Richey, and C. Bolin. “Herd Prevalence and Risk Factors of Leptospira Infection in Beef cow/Calf Operations in the United States: Leptospira Borgpetersenii Serovar Hardjo”. The Bovine Practitioner, vol. 41, no. 1, Mar. 2007, pp. 15-23, doi:10.21423/bovine-vol41no1p15-23.