Cvetanov, Genadi, and Tsanko Karadzhov. “GEOMETRIC SYNTHESIS OF INVOLUTE PLANETARY GEARS WITH CONNECTED GEAR WHEELS OF TYPE 2K-H”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference, vol. 3, June 2021, pp. 49-53, https://doi.org/10.17770/etr2021vol3.6643.