Nogueira Filho, J. C. M., C. de S. Lucci, L. Melotti, M. E. M. de Oliveira, C. G. de Lima, and J. A. da Cunha. “Differencial Rumen Protozoa Counting from Steers Fed Napier Elephant Grass (Pennisetum Purpureum Schum) at Different Maturity Stages”. Brazilian Journal of Veterinary Research and Animal Science, vol. 29, no. 2, Dec. 1992, pp. 215-21, doi:10.11606/issn.1678-4456.bjvras.1992.51987.