| Number | Name | Date | Kind |
|---|---|---|---|
| 580542 | Battey | Apr 1897 | |
| 803059 | Hill | Oct 1905 | |
| 2009905 | Rankin | Jul 1935 | |
| 2181116 | Boyle | Nov 1939 |
| Number | Date | Country |
|---|---|---|
| 604792 | Sep 1978 | CHX |
| 2064965 | Jun 1981 | GBX |
| Entry |
|---|
| "Creative Puzzles of the World", by Van Delft & Botermans, published by Harry N. Abrams, .COPYRGT.1978, p. 70. |