TY  - RPRT
TI  - Letter Circular 977: standards and specifications for building and construction materials, fixtures, supplies, and equipment (superseding Letter Circular 941)
PY  - 1950
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 977
DO  - 10.6028/NBS.LCIRC.977
ER  -