Number | Date | Country | Kind |
---|---|---|---|
54/100593 | Aug 1979 | JPX |
Number | Name | Date | Kind |
---|---|---|---|
2592368 | Yackel | Apr 1952 | |
2685510 | Yackel | Aug 1954 | |
2751295 | Salminen et al. | Jun 1956 | |
2856283 | Yackel et al. | Oct 1958 | |
3143414 | Yackel et al. | Aug 1964 | |
3440049 | Moede | Apr 1969 | |
3639126 | Verelst | Feb 1972 |
Entry |
---|
Pontius, Photographic Science and Technique, PSA Journal, Section B, Sep. 1951, pp. 76-79. |