1. Progress report on Mandarin tone study;Brotzman,1964
2. Cross-linguistic study of categorical perception for lexical tone;Chan;Journal of the Acoustical Society of America,1975
3. Mandarin primer;Chao,1948
4. A grammar of spoken Chinese;Chao,1968
5. The acoustical features and perceptual cues of the four tones of standard colloquial Chinese;Chuang,1972