1. Agatsuma, T. (1985) An investigation of words description and recognition abilities of hearing impaired children. National Institute of Special Needs Education Bulletin, 12, 91–98. (in Japanese)
2. Agatsuma, T. (1991) An investigation of word description abilities of hearing-impaired children. Bulletin of Joetsu University of Education, 10, 155–164. (in Japanese)
3. Amano, K. (1970) Formation of the act of analyzing phonemic structure of words and its relation to learning Japanese syllabic characters (kanamoji). Japanese Journal of Educational Psychology, 18, 76–89.
4. Amano, K. (1986) Learning process of characters in children. Akiyama Shuppan, Tokyo. (in Japanese)
5. Benett, C. W. & Ling, D. (1973) Discrimination of the voiced-voiceless distinction by severely hearing-impaired children. The Journal of Auditory Research, 13, 271–279.