1. Dudley , D. ( 1962 ).Gear Handbook, The Design, Manufacture, and Application of Gears. McGraw-Hill Publishing Company , New York , Chapter 21 , pp. 1 – 26 .
2. Taec , B. ( 1975 ).Production of Toothed Gears. Machinestroene , Moscow , USSR , Chapter 13 , pp. 557 – 613 .
3. Litvin , F. ( 1962 ).New Type of Cylindrical Wormgearing. Mashgiz , Moscow , USSR , p. 102 .