Testing respiratory protective equipment for approval

Author:	Schrenk, H. H.
Year:	1940
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7130
Series:	Information circular / United States. Bureau of Mines ;
Report Number:	7130
Subjects:	Respirators (Medical equipment)
	Breathing apparatus
Link:	https://hdl.handle.net/2027/mdp.39015078534362