1. John J. Coy, Robert C. Bill: Advanced transmission studies. 44th Annual Forum of the American helicopter Society, June 16-18, (1988).
2. H. Chin, K. Danai, D.G. Lewicki: Efficient fault diagnosis of helicopter gearboxes. Technical Report, F-5019.
3. David M. Blunt, Jonathan A. Keller: Mechanical Systems and Signal Processing, (2006), p. (2095).
4. Andrew M. Mitchell. Testing of UH-60A helicopter transmission in NASA Lewis 2240-kW (3000-hp) facility. NASA Contractor report 2626, 986.
5. G. White: IMechE, Vol 196(1982), p.11.