TY - RPRT TI - Letter Circular 235: the ultra-violet transmission of various new glasses and window glass substitutes as compared with that of common window glass PY - 1928 PB - National Institute of Standards and Technology CY - Gaithersburg, MD SN - LCIRC 235r1928 DO - 10.6028/NBS.LCIRC.235r1928 ER -