TY  - RPRT
TI  - Letter Circular 518: the corrosively of soils (supersedes Letter Circular 433)
PY  - 1938
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - LCIRC 518
DO  - 10.6028/NBS.LCIRC.518
ER  -