01194nam 2200325Ka 450 991069645440332120080307084557.0(CKB)5470000002378297(OCoLC)213068129(EXLCZ)99547000000237829720080307d1997 ua 0engtxtrdacontentcrdamediacrrdacarrierRoof hazard alert modules[electronic resource][Pittsburgh, PA] :U.S. Dept. of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health,[1997]2 unnumbered pages digital, PDF fileTechnology news ;no. 455Title from title screen (viewed on Mar. 7, 2008)."May 1997."Mine roof controlUnited StatesEquipment and suppliesMine roof controlEquipment and supplies.National Institute for Occupational Safety and Health.GPOGPOBOOK9910696454403321Roof hazard alert modules3164760UNINA