المؤلفون: Getzin, Anne E., Knox, Kjersti E., Bergum, Alison, Read, Lindsay, Jenkins, Ceri, Rieselbach, Richard, Kniss, Chad, Oliver, Thomas R., Friedsam, Donna

المصدر: Wisconsin Medical Journal; Sep2009, Vol. 108 Issue 6, p302-309, 8p, 5 Charts, 3 Graphs