title: Open but not free--publishing in the 21st century.
authors: American Physiological Society, Bethesda, MD, USA.
authors: Martin
authors: M
authors: Frank
mesh_terms: D022126:Access to Information; D035843:Biomedical Research / Q000191:economics*; D019992:Databases as Topic; D033181:Information Dissemination / Q000379:methods*; D020407:Internet; D009317:National Library of Medicine (U.S.); D010506:Periodicals as Topic / Q000191:economics*; D011643:Publishing / Q000191:economics*; D014481:United States