1. Kudreavtev, V.N., Gierzaves, I.A., Glukharev, E.G.: Design and Calculus of Gearboxes. Mashinostroenie Publishing, Sankt Petersburg (1971). (in Russian)
2. Chat, T.: Some problems of kinematics calculation of transmission mechanics system. In: Proceedings of the National Conference on Engineering Mechanics, vol. 2 (Hanoi), pp. 7–12 (1993). (in Vietnamese)
3. Milou, G., Dobre, G., Visa, F., Vitila, H.: Optimal design of two step gear units, regarding the main parameters. VDI Berichte, no. 1230, p. 227 (1996)
4. Pi, V.N.: A method for optimal calculation of total transmission ratio of two step helical gearboxes. In: Proceedings of the National Conference on Engineering Mechanics, Ha Noi, p. 12 (2001)
5. Cam, N.T.H., Pi, V.N., Tuan, N.K., Hung, L.X., Thao, T.T.P.: Determining optimal partial transmission ratios of mechanical driven systems using a V-Belt drive and a helical reducer with second-step double gear-sets. In: Fujita, H., Nguyen, D., Vu, N., Banh, T., Puta, H. (eds.) ICERA 2018. LNNS, vol. 63, pp. 261–269. Springer, Cham (2019)