PT - JOURNAL ARTICLE AU - Nelson, Carl L. TI - Introduction DP - 1973 Sep 21 TA - Cleveland Clinic Journal of Medicine PG - 97--98 VI - 40 IP - 3 4099 - http://www.ccjm.org/content/40/3/97.short 4100 - http://www.ccjm.org/content/40/3/97.full SO - Cleve Clin J Med1973 Sep 21; 40