1. Ultrasonic flaw detection;Byrne,1956
2. 20 years of ultrasonic axle testing — established methods and more recent developments in the DB and other railways;Egelkraut;Rail International,1970
3. Ultrasonic testing of railway axles;Wise,1969
4. Axles — a fatigue problem;Burdon,1967
5. Chief mechanical and electrical engineers standing order,1977