1. W. Lewis, Investigation of the strength of gear teeth, in: Proceedings of the Engineers Club of Philadelphia, 1892. pp16-23.
2. The strength of gear teeth;Timoshenko;Mech. Eng.,1926
3. Tensile fillet stresses in loaded projections;Heywood;Proc. Inst. Mech. Eng.,1948
4. Bending stresses in spur gear teeth: proposed new design factors based on a photo-elastic investigation;Jacobson;Proc. Inst. Mech. Eng.,1955
5. The beam strength of modern gear-tooth design;Kelley;SAE Tech. Pap.,1958