1. Laver, J.D.: The Phonetic Description of Voice Quality, (Cambridge University Press 1980)
2. Holmes, J.N.: Speech Synthesis, (Mills and Boon, London 1972)
3. ‘Speech at High Ambient Air Pressure’, Quarterly Progress Report, 5IL-QPSR, Speech Transmission Lab, Stockholm, 1964 p. 9–21 5IL-QPSR