1. Qualitative analysis of wear — progress report No. 15 of the ASME Special Research Committee on Strength of Gear Teeth;Buckingham;Mech. Eng.,1937
2. Gear failures;Frederick,1958
3. Gear failures;Shipley;Mach. Des.,1967
4. Nomenclature of gear-tooth wear and failure;American Gear Manufacturers Association;AGMA Publ. 110.03,1964