1. 1. Ministry of Health, Labour and Welfare, Summary of Vital Statistics, (http://www.mhlw.go.jp/english/database/db-hw/populate/index.html)
2. 2. Japanese Foundation for Cancer Research (http://www.jfcr.or.jp/english/about/index.html)
3. 3. The Japan Cancer Society (http://www.jcancer.jp)
4. 4. Moore MA, Sobue T: Cancer research and control activities in Japan: contributions to international efforts. Asian Pac J Cancer Prev 10: 183-200, 2009
5. 5. The center for cancer control and information services, National cancer center: History of cancer control in Japan, Cancer statistics in Japan and Cancer mortality (1958-2008) (http://ganjoho.ncc.go.jp/professional/statistics/statistics.html)