| Number | Name | Date | Kind |
|---|---|---|---|
| 1817522 | Price | Aug 1931 | |
| 1843738 | Schubert | Feb 1932 | |
| 1939821 | Lawrence | Dec 1933 | |
| 2191947 | Allen et al. | Feb 1940 | |
| 2755202 | Balon et al. | Jul 1956 | |
| 2767650 | Yunker et al. | Oct 1956 | |
| 2836152 | Rosenblum | May 1958 | |
| 3013917 | Karlan et al. | Dec 1961 | |
| 3065120 | Avelar | Nov 1962 | |
| 3114447 | Wolowitz | Dec 1963 | |
| 3225888 | Javors | Dec 1965 | |
| 3297507 | Twomey | Jan 1967 | |
| 3298850 | Reed et al. | Jan 1967 | |
| 3410251 | Glenn et al. | Nov 1968 | |
| 3459127 | Barouh | Aug 1969 | |
| 3515572 | Dabisch | Jun 1970 | |
| 3519456 | Reed et al. | Jul 1970 |
| Number | Date | Country |
|---|---|---|
| 816,022 | Jun 1969 | CA |
| 932,937 | Jul 1963 | UK |
| Entry |
|---|
| American Ink Maker, Jan. 1946, pp. 23-26. |
| American Ink Maker, Mar. 1950, pp. 29-32, 63. |
| American Ink Maker, Apr. 1950, pp. 27-29, 53, 55. |