TY  - RPRT
TI  - The computation of second vertical derivatives of geomagnetic fields
AU  - Roland G. Henderson
AU  - Isadore Zietz
PY  - 1949
DO  - 10.1190/1.1437558
UR  - https://pubs.usgs.gov/publication/70215625
ID  - 70215625
ER  -