1. RD 32.144-2000: Acceptance Nondestructive Testing. Solid Wheels, Tires, and Axles of Rolling-Stock Wheel Pairs. Specifications, 2000.
2. GOST (State Standard) 30237-96 (ISO 1005-3-82): Finished Axles for Rolling-Stock of 1520-mm-Track Railways. Technical Specifications, 1996.
3. Ermolov, I.N., Vopilkin, A.Kh., and Badalyan, V.G., Raschety v ultrazvukovoi defektoskopii (kratkii spravochnik) (Calculations in Nondestructive Flaw Detection. Brief Handbook), Moscow: NPTs NK Ekho+, 2000.
4. Ermolov, I.N., Teoriya i praktika ul?trazvukovogo kontrolya (Theory and Practice of Ultrasonic Inspection), Moscow: Mashinostroenie, 1981.
5. Friedlander, F., Sound Pulses, Cambridge: 1958. Translated under the title Zvukovye impulsy, Moscow: Inostrannaya Literatura, 1962.