DIN_3994_1963-08_ge_Addendum modification of straight spur gears in the 05-syste DIN_3990-2_1987-12_en_Calculation of load capacity of cylindrical gears_calculat DIN_3990-21_1989-02_ge_Calculation of load capacity of cylindrical gears_applicaDIN_3990-5_1987-12_en_Calculation of load capacity of cylindrical gears_Enduranc