Electroacoustics : Microphones, earphones and loudspeakers / by M. L. Gayford. Gayford, M. L. Electroacoustic transducers. TK5981 .G32 621.3818 GAE includes index. Bibliography: p. 282-284. London : Newnes-Butterworth ; c1970. c1970. 1970 Text xii, 289 p. : eng STC monograph