1. Ultrasonics;Rod;Industrial Research,1968
2. Ultrasonics in industry;Steinberg;Proceedings of the IEEE,1965
3. Ultrasonics in industry today;Jacke,1972
4. Recent advances in sonochemical engineering;Fogler;Chem Eng Prog Symp Ser,1971
5. Primo, Y.E., Lafuentte, B.F., Perez, R.P., Oriol, C.I., Jorro, M.M. Spanish patent 384 195 (1 January 1973)