| Number | Date | Country | Kind |
|---|---|---|---|
| 8300775 | Jan 1983 | GBX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3173387 | Cree, Jr. | Mar 1965 | |
| 3196813 | McHugh, Jr. | Jul 1965 |
| Number | Date | Country |
|---|---|---|
| 304751 | Apr 1955 | CHX |
| 494232 | Oct 1938 | GBX |
| 2075570 | Nov 1981 | GBX |
| 2121950 | Jan 1984 | GBX |
| Entry |
|---|
| Technical Manual, Gasproof Shelters, U.S. War Dept., May 12, 1943, pp. 9-52. |
| The Electrolysis of Water, Joseph W. Richards, pp. 22, 23 & 76-80, 1904. |