TY - RPRT TI - Circular of the Bureau of Standards no. 469: optical glass at the National Bureau of Standards AU - Glaze, Francis W AU - Hahner, Clarence H PY - 1948 PB - National Bureau of Standards CY - Gaithersburg, MD SN - NBS CIRC 469 DO - 10.6028/NBS.CIRC.469 ER -