1. American Standard Specification for Ultrasonic Therapeutic Equipment;American Standards Institute,1956
2. ‘Radiation force and force balances’;Beissner,1993
3. ‘A review of instrumentation available for therapeutic ultrasound’;Docker;Physiotherapy,1987
4. ‘The importance of measurement of effective transducer radiating area in the testing and calibration of therapeutic ultrasonic instruments’;Fyfe;Health Physics,1982
5. ‘Evaluation of ultrasound therapy devices’;Hekkenberg;Physiotherapy,1986