| Number | Name | Date | Kind |
|---|---|---|---|
| 814503 | Andresen et al. | Mar 1906 | |
| 2543427 | Warne | Feb 1951 | |
| 3217917 | George | Nov 1965 | |
| 3433378 | Ross | Mar 1969 | |
| 3581927 | Langdon | Jun 1971 | |
| 3684120 | Beeman | Aug 1972 | |
| 3826395 | Montgomery | Jul 1974 | |
| 4269319 | Rubens | May 1981 | |
| 4336891 | Smith | Jun 1982 | |
| 4349056 | Heino | Sep 1982 | |
| 4416381 | Swartwout | Nov 1983 | |
| 4566508 | Bowyer | Jan 1986 | |
| 4566509 | Szajna | Jan 1986 |
| Number | Date | Country |
|---|---|---|
| 0109704 | May 1984 | EPX |
| Entry |
|---|
| Research Disclosure, No. 106, Feb. 1973, Disclosed Anonymously. |