Bartels, Julius <br/><br/>
Geomagnetic indices K and C, 1951 
Julius Bartels and J. Veldkamp  
 - Washington, D. C.  International Union of Geodesy and Geophysics   1952 
 - vi+106p. 
 - International Association of Terrestrial Magnetism and Electricity Bulletin; No. 12f .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Iatme Bulletin No.12fIaga Bulletin-dataIaga IndicesIatme BulletinIugg
<br/><br/><label>Universal Decimal Class. No.: </label>550.38  / IAGA