1. Progress in the field of non-destructive testing through the use of ultrasonics;Hitt,1952
2. Ultrasonic flaw evaluation;Hitt;Western Machinery and Steel World,1957
3. ASTM Specification E 127-64
4. Ultrasonic flaw detection in metals;Bradfield,1960
5. Stress wave propagation as applied to the detection of flaws by ultrasonic inspection;Christie,1958