TY  - RPRT
TI  - Letter Circular 698: hardened copper (revision of Letter Circular 61 and 444)
PY  - 1942
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 698
DO  - 10.6028/NBS.LCIRC.698
ER  -