List of respiratory protective devices approved by the Bureau of Mines

Author:	Schrenk, H. H.
Year:	1943
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7237
Series:	Information circular ;
Report Number:	7237
Subjects:	Respirators (Medical equipment)
	Mineral industries--Safety measures
	Breathing apparatus
	Gas masks
Link:	https://hdl.handle.net/2027/mdp.39015074126916