TY  - BOOK
ED  - United States.
TI  - Grids and magnetic declinations ..
T2  - Its A.M.S. memorandum
AV  - UG470 .U5 no. 425
PY  - 1945///]
CY  - [Washington
KW  - Military maps
KW  - Geomagnetism
N1  - "Amendment no. 1" ([2] p.) inserted
ER  -