TY  - RPRT
TI  - Letter Circular 429: information on ultraviolet transparency of window materials and fabrics (supersedes Letter Circular 235 and Form Letter PC 113)
PY  - 1934
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 429
DO  - 10.6028/NBS.LCIRC.429
ER  -