Fowler, M.E. (2010). "Medicine and Surgery of Camelids", Ames, Iowa: Wiley-Blackwell. Chapter 1 General Biology and Evolution addresses the fact that camelids (including camels and llamas) are not ruminants, pseudo-ruminants, or modified ruminants.
Fernández, Manuel Hernández; Vrba, Elisabeth S. (1 de maio de 2005). «A complete estimate of the phylogenetic relationships in Ruminantia: a dated species-level supertree of the extant ruminants». Biological Reviews. 80 (2): 269–302. ISSN1469-185X. PMID15921052. doi:10.1017/s1464793104006670
Austin, PJ; et al. (1989). «Tannin-binding proteins in saliva of deer and their absence in saliva of sheep and cattle». J Chem Ecol. 15 (4): 1335–47. PMID24272016. doi:10.1007/BF01014834
Asanuma, Narito; Iwamoto, Miwa; Hino, Tsuneo (1999). «Effect of the Addition of Fumarate on Methane Production by Ruminal Microorganisms in Vitro». Journal of Dairy Science. 82 (4): 780–787. PMID10212465. doi:10.3168/jds.S0022-0302(99)75296-3
Fernández, Manuel Hernández; Vrba, Elisabeth S. (1 de maio de 2005). «A complete estimate of the phylogenetic relationships in Ruminantia: a dated species-level supertree of the extant ruminants». Biological Reviews. 80 (2): 269–302. ISSN1469-185X. PMID15921052. doi:10.1017/s1464793104006670
Austin, PJ; et al. (1989). «Tannin-binding proteins in saliva of deer and their absence in saliva of sheep and cattle». J Chem Ecol. 15 (4): 1335–47. PMID24272016. doi:10.1007/BF01014834
Asanuma, Narito; Iwamoto, Miwa; Hino, Tsuneo (1999). «Effect of the Addition of Fumarate on Methane Production by Ruminal Microorganisms in Vitro». Journal of Dairy Science. 82 (4): 780–787. PMID10212465. doi:10.3168/jds.S0022-0302(99)75296-3
Ripple, William J.; Pete Smith; Helmut Haberl; Stephen A. Montzka; Clive McAlpine & Douglas H. Boucher. 2014. "Ruminants, climate change and climate policy". Nature Climate Change. Volume 4 No. 1. pp. 2–5.
Fernández, Manuel Hernández; Vrba, Elisabeth S. (1 de maio de 2005). «A complete estimate of the phylogenetic relationships in Ruminantia: a dated species-level supertree of the extant ruminants». Biological Reviews. 80 (2): 269–302. ISSN1469-185X. PMID15921052. doi:10.1017/s1464793104006670