TY - GEN AU - F W Smither C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1939-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.CIRC.424 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1939 TI - Circular of the Bureau of Standards no. 424::washing, cleaning, and polishing materials ER -