The principles of MEDLARS MEDLARS National Library of Medicine (U.S.) MEDLARS Libraries, Medical Electronic Data Processing Information Systems Bethesda, Md. : U.S. Dept. of Health, Education and Welfare, Public Health Service, National Institutes of Health, National Library of Medicine ; Washington, D.C. : For sale by the Supt. of Docs., U.S. G.P.O., [1970] Text Illustrations 77 p. nlm:nlmuid-0243515-bk 0243515 http://resource.nlm.nih.gov/0243515 OCLC: 83935 English The National Library of Medicine believes this item to be in the public domain : https://creativecommons.org/publicdomain/mark/1.0/