TY  - RPRT
TI  - Letter Circular 812: artificial abrasives and abrasive products (replaces Letter Circular 540)
PY  - 1945
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 812
DO  - 10.6028/NBS.LCIRC.812
ER  -