John Esling (1990):``Computer Coding of the IPA: Supplementary Report''. Journal of the International Phonetic Association, vol. 20(1).
John Esling and Harry Gaylord (1993):``Computer Codes for Phonetic Symbols''. Journal of the International Phonetic Association, vol. 23(2): 83-97.
Unicode Inc. (1991):``The Unicode Standard: Worldwide Character Encoding Version 1.0'', Addison Wesley, ISBN 0-201-56788-1