TY - GEN AU - Clara Sentel C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1948-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.LCIRC.915 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1948 TI - Letter Circular 915::painting exterior walls of porous masonry (superseding Letter Circular 747) ER -