1. Bair, B. W. and Tsay, C. B., 1998, “ZK-Type Dual-Lead Worm and Worm-Gear Drives: Contact Teeth, Contact Ratio and Kinematic Errors,”ASME Journal of Mechanical Design, Vol. 120, pp. 422–428.
2. Buckingham, E., 1963. “Analytical Mechanics of Gears” 2nd ed. Dover Publication.
3. Colbourne, J. R., 1989, “The Use of Oversize Hobs to Cut Worm Gears,” AGMA paper 89FTB8.
4. Dudley, D. W.,Gear Handbook. The Design, Manufacture, and Application of Gears. McGraw-Hill, NY, 1962.
5. Dudley, D. W., 1954.Practical Gear Handbook, McGraw-Hill, NY.