1. Ahvenainen et al. (1989). Lebensmittel. Wissenschaft und Technologie, 22, 382
2. Bhatia, A. B. (1967). Ultrasonic absorption. an introduction to the theory of sound absorption and dispersion in gases liquids and solids. New York: Dover Publications
3. Black, J. O. et al. (1983). US Pat 4,384,476
4. Chivers et al. (1995). Ultrasonics, 33 (1), 75
5. CRC handbook of chemistry and physics (67th ed.). Boca Raton, Florida: CRC Press, 1986