Soo-Quee Koh David, Choon-Huat Koh Gerald
Department of Community, Occupational and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Block MD3, 16 Medical Drive, Singapore 117597, Singapore.
Occup Environ Med. 2007 Mar;64(3):202-10. doi: 10.1136/oem.2006.026567.