E. ÁVILA GONZÁLEZ, S. GÓMEZ ROSALES, J. ARCE MENOCAL, C. LÓPEZ COELLO, M. D. J. ORDÓNEZ, and P. A. VELASQUEZ MADRAZO, “Effect of energy source and level on the length of intestinal villi, immune response and the production performance in broilers”, Vet Mex OA, vol. 39, no. 004, Oct. 2009.