| Author: | Pearce, S. J. | 
|---|---|
| Year: | 1957 | 
| Document Type: | USBI | 
| Issuing Agency: | U.S. Dept. of the Interior, Bureau of Mines, | 
| SUDOC: | I 28.27:7792 | 
| Series: | Information circular / United States. Bureau of Mines ; | 
| Report Number: | 7792 | 
| Subjects: | Respirators (Medical equipment) | 
| Breathing apparatus | |
| Link: | https://hdl.handle.net/2027/mdp.39015078459917 |