1. American National Standards Institute (1969) ANSI S3.5–1969: Methods for calculation of the articulation index
2. American National Standards Institute (1997) ANSI S3.5–1997: Methods for calculation of the articulation index
3. American Society for Testing and Materials International (2002) ASTM E1130-02e1: Standard test method for objective measurement of speech privacy in open offices using articulation index. American Society for Testing and Materials International New York
4. American Society for Testing and Materials International (1969) ASTM E1374 Standard guide for open office acoustics
5. Bench J, Bamford J (1979) Speech-hearing tests and the spoken language of hearing-impaired children. Academic Press, London