1. D. Nicholas, Orientation and frequency dependence of backscattered energy. In: “Recent advances in Ultrasound in Medicine,” D.N. White, Ed. (Research Studies Press, Forest Grove) pp. 29–54 (1977).
2. B. Fay, Ermittlung der Korngröße von Stahl mit dem Verfahren der Ultraschallrückstreuung. Arch. Eisenhüttenwes. 47, pp. 119–126 (1976).
3. H.P. Hougardy, Vergleich der metallographisch und durch Ultraschallrückstreuung ermittelten Korngröße von Stahl. Arch. Eisenhütenwes. 47, pp. 127–130 (1976).
4. B. Fay, Ultrasonic backscattering, a method for non-destructive structure testing. IEEE-Ultrasonics Symp. Proc., pp. 51–53 (1976).
5. C.R. Hill, R.C. Chivers, R. W. Huggins and D. Nicholas, Scattering of ultrasound by human tissue. Ultrasound: Its application in medicine and biology, Part 1, Elsevier scientific publishing company, pp. 441–493 (1977).