RT Journal Article SR Electronic T1 Textbook of Internal Medicine. Second Edition JF The Journal of the American Board of Family Practice JO J Am Board Fam Med FD American Board of Family Medicine SP 454 OP 455 DO 10.3122/jabfm.5.4.454 VO 5 IS 4 A1 Norris, Thomas E. YR 1992 UL http://www.jabfm.org/content/5/4/454.abstract AB