1. 1) Aoki S, Kawabe R, Chikumaru H, Hirota M, Miyake T, Omura S, Fujita K (2003) Ten-year clinico-statistical study of oral squamous cell carcinoma. Yokohama Igaku 54:539-546. (in Japanese)
2. 2) Hasegawa Y, Takezaki T (2000) Epidemiology of tongue cancer. JOHNS 16:549-553. (in Japanese)
3. 3) Japan Society for Head and Neck Cancer Registry Committee (2006) Report of head and neck cancer registry of Japan clinical statistics of registered patients, 2002. Jpn J Head Neck Cancer 32 (Supple):1-98.
4. 4) Japan Society for Oral Tumors (Eds) (2010) General Rules for Clinical and Pathological Studies on Oral Cancer, 1st ed., pp.34, Kanehara Shuppan, Tokyo. (in Japanese)
5. 5) Japan Society for Oral Tumors, Japanese Society of Oral and Maxillofacial Surgeons (Eds) (2009) Evidence-Based Oral Cancer Treatment Guideline, 2009 ed., pp.11-13, Kanehara Shuppan, Tokyo. (in Japanese)