Tappero J W, Koehler J E, Berger T G, Cockerell C J, Lee T H, Busch M P, Stites D P, Mohle-Boetani J, Reingold A L, LeBoit P E
University of California, San Francisco.
Ann Intern Med. 1993 Mar 1;118(5):363-5. doi: 10.7326/0003-4819-118-5-199303010-00007.