Thawalwong Ratanasiri2011-02-242011-02-242010-04-062010-04-06Srinagarind Medical Journal (SMJ); Vo. 22 No. 4 October-December 2007; 471-476http://imsear.searo.who.int/handle/123456789/133524no abstracten-USAcademic Affairs, Faculty of Medicine, Khon Kaen University, KhonKaen, ThailandReview Articles