Use of reflector buttons for danger, warning, direction, and safety signs in mines

Author:	Griffith, F. E.
Additional Authors:	Van der Veer, H. J.
Year:	1937
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:6980
Series:	Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number:	6980
Subjects:	Mine safety
	Reflectors (Safety devices)
Link:	https://hdl.handle.net/2027/mdp.39015077569963