Ikuo Koike, Hajime Terauchi, Junko Matsui, Tomoko Takada. The English proficiency levels as part of necessary qualifications to work in globalized business corporations. 2008
Hideo Oka, Shigehito Miyoshi, Mika Kawanari, Shigeru Sasajima, Tomoko Takada. The development of a tentative Japanese version of common framework of reference for the English language. A final report: Second language acquisition research in order to realize consistent English language education elementary school through university (Grant-in-aid scientific research #16202010 headed by Dr. Ikuo Koike). 2008. 1-70
Tomoko Takada. A Longitudinal study of the effects of learning English in elementary school. Annual Review of English Language Education in Japan. 2008. 19. 231-240