| Number | Name | Date | Kind |
|---|---|---|---|
| 3191177 | Parzen | Jun 1965 | |
| 4219821 | Selim | Aug 1980 |
| Entry |
|---|
| Radio News, Jan. 1937, p. 396, top left of page. |
| Murphy, An Evaluation of Shore-Based Radio Direction Finding, U.S. Department of Transportation, Sep. 1978, pp. 2-16, 4-4 and 4-20. |