February 14, 2014 The file mtrees2003.txt is the NLM MeSH (Medical Subject Headings) file for the year 2003. It is presently out of date for clinical purposes and should not be used for same. It is used here only for purposes of illustrating indexing techniques and research. For information on NLM services, contact: Customer Service National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894 Telephone: 1-888-FINDNLM (1-888-346-3656) or (301) 594-5983 e-mail: custserv@nlm.nih.gov