TY - RPRT TI - Performance tests of two throw-away type "Dustgard" air filters : manufactured by American Rock Wool Corporation Wabash, Indiana AU - Coblentz, Carl W AU - Achenbach, Paul R PY - 1959 PB - National Bureau of Standards CY - Gaithersburg, MD SN - NBS RPT 6408 DO - 10.6028/NBS.RPT.6408 ER -