http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Procedure for permitting the use of belt air to ventilate working sections of underground coal mines
Title from subject line (viewed on July 1, 2013).
"Effective Date: 05/07/2012, Expiration Date: 03/31/2014."
Procedure instruction letter ; no. I12-V-14