List of respiratory protective devices approved by the Bureau of Mines

Author:	Schrenk, H. H.
Year:	1948
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7444
Series:	Information circular / Bureau of Mines ;
Report Number:	7444
Subjects:	Respirators (Medical equipment)
	Breathing apparatus
	Mineral industries--Safety measures
	Gas masks
Link:	https://hdl.handle.net/2027/mdp.39015077577776