1. Takahaski, H., Ouchi, T. and Wagai, T.: Application of ultrasound in urology. In: XIII Congrés de la Société Internationale d’Urologie, vol. II, p. 470, 1965.
2. Die Ultraschaldiagnostik in der Urologie;Kratochwil;Wien. Klin. Wochenschr.,1970
3. McKinney, W. M.: Scientific exhibit. Seventeenth annual meeting of American Institute of Ultrasound in Medicine, Philadelphia, Pennsylvania, 1972.
4. Diagnostic application of ultrasonotomography to the prostate;Watanabe;Invest. Urol.,1971
5. Ultrasonic estimation of the volume of the enlarged prostate;Whittingham;Brit. J. Radiol.,1973