Miyagi, K., Sano, K., Morita, C., Imura, S., Morimatsu, S., Goto, T., Nakano, Y., Hashimoto, S., Matsumoto, Y., Maeda, K., Omura, K., Takarada, Y. and Honda, T. : An improved method for detecting faecal Vibrio cholerae by PCR of the toxin A gene. J. Med. Microbiol. 48 :883-889, 1999.