A directory of geomagnetic observatories with high-resolution digital results, 1987 [electronic resource] / by K.L. Svendsen, S.J. McLean, W.V. Flanagan ; in cooperation with IAGA/IUGG, Division V, Magnetic Observatories, Instruments, Indices, and Data.
Publication Info.
Boulder, Colorado : U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Geophysical Data Center, 1987.