Ingenious Ring and Puzzle Book
By Chung-En Yu. Translated by Yenna Wu. 1981. 44 pages,spiral bound.
Translation printed by Jerry Slocum, and signed by him in 1996. Very scarce.
Ingenious Rings by Yu Chong En and Zhang Wei. 152 pages. In Chinese. Translated printed by Jerry Slocum. See above book.
The Amazing Rop Rings. By Wang Zong Yi 230 page paperback. 2003, Shenyang Press. Page 1 frayed around the edges. Otherwise good condition.