[1] Univ New Mexico, Hlth Sci Lib & Informat Ctr, MSC 09 5100,1 Univ New Mexico, Albuquerque, NM 87131 USA
[2] BMJ Publishing Grp, London, England
[3] Vrije Univ Amsterdam, Fac Humanities, Dept Philosophy, Boelelaan 1105, NL-1081 HV Amsterdam, Netherlands
[4] Vrije Univ Amsterdam, Amsterdam UMC, Dept Epidemiol & Data Sci, Boelelaan 1089a, NL-1081 HV Amsterdam, Netherlands
[5] Ottawa Hosp, Res Inst, Ctr Journalol, Clin Epidemiol Program,Ctr Practice Changing Res, Gen Campus,501 Smyth Rd,POB 201B, Ottawa, ON K1H 8L6, Canada
[6] Univ Toronto, Gerstein Sci Informat Ctr, Toronto, ON, Canada
[7] Univ Manchester, Manchester Acad Hlth Sci Ctr, Ctr Biostat, Manchester, Lancs, England
[8] Maastricht Univ, Med Ctr, Sch Nutr & Translat Res Metabolisms, Care & Hlth Res Inst,Dept Epidemiol, POB 616, NL-6200 MD Maastricht, Netherlands