1. The magnetic field in the United States, 1985. [cartographic material] / Vertical intensity chart
1988. 2002-06-01T04:00:00Z. 2016-07-27T21:14:03Z. Geological Survey (U.S.). U.S. Geological Survey ; For sale by Map Distribution. English. cartographic image. Public. United States, Alaska, Hawaii, Alaska., Hawaii., and United States.
