Geomagnetic indices k and c, 1951
Bartels, J
Geomagnetic indices k and c, 1951 J. Bartels and J Veldkemp - Washington 1952
Geomagnetic indices
083.550.38 / IATME-12F
Geomagnetic indices k and c, 1951 J. Bartels and J Veldkemp - Washington 1952
Geomagnetic indices
083.550.38 / IATME-12F