Number | Name | Date | Kind |
---|---|---|---|
2914787 | Hartkopf | Dec 1959 | A |
4435798 | Taub | Mar 1984 | A |
4495670 | Baker | Jan 1985 | A |
5155911 | Collins | Oct 1992 | A |
5211322 | Nealy | May 1993 | A |
5560067 | Brook | Oct 1996 | A |
5704088 | Cerroni | Jan 1998 | A |
6182320 | Kruger et al. | Feb 2001 | B1 |
Number | Date | Country |
---|---|---|
0587268 | Apr 1925 | FR |
Entry |
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English translation of FR 587,268 to Petit, published Apr. 1925.* |
http://isd.ingham.k12.mi.us/˜goals2k/lessons/sciencelesson/stone2.html, Sandy Stone, May 2000.* |
http://www.tricitiesonline.com/kids/kidsneat.htm, 1998, Advanced Internet Marketing Solutions.* |
The New York Times, Jun. 20, 1948. |