1. Anderson, W.A., Arnold, J.T., Clark, L.D., Davids, W.T., Hillard, W.J., Lehr, W.J., Zitelli, L.T. (1977), A new real-time phased-array sector scanner for imaging the entire adult human heart, in White, D., Brown, R.E. (eds.), Ultrasound in Med., Vol. 3B, Plenum Press, New York.
2. Baker, D.W., Johnson, S.L. (1975), Doppler echocardiography, in Cardiac Ultrasound, Gramiak, R., Waag, R.C. (eds.), Mosby Press, St. Louis, pp. 264–276.
3. Barber, F.E., Lees, S., Lobene, R.R. (1969), Ultrasonic pulse—echo measurements in teeth, Archs. Oral Biol.
14: 745.
4. Barber, F.E., Baker, D.W., Nation, A.W.C., Strandness, D.E., Jr., Reid, J.M. (1974), Ultrasonic duplex echo-Doppler scanner, IEEE Trans. Biomed. Eng. BME
21: 109.
5. Beranek, L.L. (1963a), Acoustical definitions, American Institute of Physics Handbook, 2nd ed., McGraw-Hill, New York, Sec. 3, p. 2.