| Number | Name | Date | Kind |
|---|---|---|---|
| 1616202 | Shook | Feb 1927 | |
| 2979157 | Clark | Apr 1961 | |
| 3250680 | Menkart et al. | Oct 1966 | |
| 3574824 | Echeandia et al. | Apr 1971 | |
| 3639568 | Schmitt | Feb 1972 | |
| 4066745 | Tomlinson et al. | Jan 1978 | |
| 4132771 | Schreiber et al. | Jan 1979 | |
| 4153680 | Seibert | May 1979 | |
| 4159316 | Jannezewaki et al. | Jun 1979 | |
| 4187287 | Schreiber et al. | Feb 1980 | |
| 4193987 | Harth et al. | Mar 1980 | |
| 4209504 | Harth et al. | Jun 1980 | |
| 4272393 | Gergely | Jun 1981 | |
| 4349533 | Dent et al. | Sep 1982 | |
| 4537764 | Pellico et al. | Aug 1985 |
| Number | Date | Country |
|---|---|---|
| 332142 | Nov 1930 | GBX |
| 1382898 | Nov 1971 | GBX |
| 1382898 | Nov 1971 | GBX |
| 1304090 | Jan 1973 | GBX |
| 2082454A | Mar 1982 | GBX |
| 2109682A | Aug 1983 | GBX |
| Entry |
|---|
| "Reports of the Institute for Medical & Dental Engineering", Nos. 3, 22-35 (1969); 4, 115-128 (1970) and 7, 85-95 (1973). |