1. Quackenbush, S.R., T., and Clements, M.A.: ‘Objective measures of speech qaulity’, (Prentice-Hall, Englewood Cliffs, NJ 1988)
2. Enhanced Itakura measure incorporating masking properties of human auditory system
3. ‘Objective scaling of sound quality for normal-hearing and hearing-impaired listeners’, Tech., Report No. 54, 1993