Ramírez de la Ribera J L, Kijora C, Acosta I L, Cisneros López M and Tamayo Soza W 2008: Effect of age and growing season on DM yield and leaf to stem ratio of different grass species and varieties growing in Cuba. Volume 20, Article #148. Retrieved , from http://www.lrrd.org/lrrd20/9/rami20148.htm