1. The non-uniqueness of phonemic solutions of phonetic systems;Chao;BIHP,1934
2. Howie J. M. (1965) Syllable-structure and phonological rules for Pekin Mandarin. Indiana University. Mimeographed work paper.
3. Peiping morphophemics;Hockett;Lg,1950
4. Vowel formant values;Brotzman;POLA,1963