1. Ramos JM, Gutierrez F, Masia M, Martin-Hidalgo A (2004) Publication of European Union research on infectious diseases (1991-2001): a bibliometric evaluation. Eur J Clin Microbiol Infect Dis 23:180–184
2. Institute for Scientific Information (2004) SCI: Science Citation Index-Journal Citation Reports. The Institute for Scientific Information, Philadelphia
3. PubMed database (2004) National Library of Medicine, Bethesda, MD. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed
4. United Nations (2004) United Nations Statistical Yearbook, 48th issue, Part 2. United Nations, New York, pp 33–132
5. World Development Indicators Online (2004) The World Bank, Washington, D.C. http://devdata.worldbank.org/dataonline/