Number | Date | Country | Kind |
---|---|---|---|
8817388 | Jul 1988 | GBX |
Number | Name | Date | Kind |
---|---|---|---|
1877661 | Heisler et al. | Sep 1932 | |
2747324 | Zalkind | May 1956 | |
3611618 | Steiner | Oct 1971 | |
4349984 | Goldfarb et al. | Sep 1982 | |
4437668 | Simpson et al. | Mar 1984 | |
4466215 | Hanazato | Aug 1984 | |
4610637 | Ferguson | Sep 1986 | |
4631040 | Shiraishi | Dec 1986 | |
4684355 | Urakawa et al. | Aug 1987 | |
4698023 | Marino | Oct 1987 |
Number | Date | Country |
---|---|---|
0085542 | Aug 1983 | EPX |
2468393 | May 1981 | FRX |
2616082 | Dec 1988 | FRX |
419311 | May 1933 | GBX |
920534 | Mar 1963 | GBX |
1357517 | Apr 1973 | GBX |
1559143 | Aug 1977 | GBX |
2042912 | Oct 1980 | GBX |
2207364 | Feb 1989 | GBX |
Entry |
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"Shape Stack", Cleo Learning Aids, 2-76, p. 175. |