| Number | Name | Date | Kind |
|---|---|---|---|
| 3291026 | Simpson | Dec 1966 | |
| 3739707 | Knapp | Jun 1973 | |
| 3984826 | Kowalsky | Oct 1976 | |
| 4088986 | Boucher | May 1978 | |
| 4340885 | Chavis et al. | Jul 1982 | |
| 4462246 | Advani et al. | Jul 1984 | |
| 4477263 | Shaver | Oct 1984 |
| Entry |
|---|
| Phoenix Precision Instrument Co., Bulletin No. IM 2000A, 1966. |
| Spectrometrics of Florida, Inc., The NO.sub.2 Analyzer, Model Vd.sup.2, 1972. |