Number | Name | Date | Kind |
---|---|---|---|
430502 | Altekruse | Jun 1890 | |
767645 | Kelly | Aug 1904 | |
781050 | Curtis | Jan 1905 | |
906450 | Murf et al. | Dec 1908 | |
943496 | Weigt | Dec 1909 | |
1225760 | Brown | May 1917 | |
1261242 | Keiser | Apr 1918 | |
1350039 | Senyk | Aug 1920 | |
1388710 | Hime | Aug 1921 | |
1425107 | Levinson | Aug 1922 | |
1455009 | Schenk | May 1923 | |
2473369 | Harris | Jun 1949 | |
2836421 | Turner | May 1958 | |
3372936 | Sanson | Mar 1968 | |
3638949 | Thompson | Feb 1972 | |
3721448 | Coffin | Mar 1973 | |
4148489 | Pidgeon | Apr 1979 | |
4534563 | Guenther | Aug 1985 |
Entry |
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"Puzzles Old & New", by J. Slocum & J. Botermans, copyright 1986, publ. by Plenary Publications Int., The Netherlands, p. 9. |
Journal of Recreational Mathematics, vol. 10(4), 1977-78, copyright 1978, Article entitled "The Six-Piece Burr", by William H. Cutler, pp. 241-250. |
Puzzles Old and New by Jerry Slocum, pp. 82, 83 and 154, (1986). |
Puzzles in Wood by E. M. Wyatt, (1956). |