1. Development and classification of worm drive;Chen,2015
2. Hourglass Worm Drive Design and Modification(in Chinese);Dong,2004
3. E. Wildhaber, Wildhaber worm drive, in, United States Patent 3386305, 1966.
4. A study on the hourglass worm gearing whose wheel has the helical teeth(1st report);Maki;Trans. Jpn. Soc. Mech. Eng. Part C,1995
5. A study on the hourglass worm gearing whose wheel has the helical teeth(2nd report);Okamoto;Trans. Jpn. Soc. Mech. Eng. Part C,1996