Number | Name | Date | Kind |
---|---|---|---|
3248401 | Tondeur et al. | Apr 1966 | |
3394125 | Crenshaw | Jul 1968 | |
3637659 | Plostnieks | Jan 1972 |
Entry |
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Derwent Abst. No. 71954S -- Belgian Pat. 766392 June 22, 1970. |
Derwent Abst. No. 81178T -- Belgian Pat. 784260 June 25, 1971. |
Derwent Abst. No. 21007V -- Belgian Pat. 804550 Sept. 19, 1972. |
Derwent Abst. No. 66559V German Pat. 2,408,476 Mar. 2, 1973. |