Browning, M. (2000) Antiviral Immunity. [on line] http://www.tulane.edu/dmsander/www/MBChB/8a.html

PubMed (Medline) Access to a data  base with scientific publications, biomedical and veterinary http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed 

Roit, I, Brostoff, J., Male, D. (1998). Inmunología. (4^th edition). Editorial Harcourt Brace. Madrid. Chapter 19.

Tizard, Ian. (1998) Inmunología Veterinaria (5^th edition). Mc Graw-Hill Interamericana. Healthcare Group. Mexico. Chapter 21.