TY  - RPRT
TI  - Letter Circular 613: automobile engine lubricating oils (supersedes Letter Circular 407)
PY  - 1940
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 613r1940
DO  - 10.6028/NBS.LCIRC.613r1940
ER  -