Bartels, Julius,  1899- <br/><br/>
Geomagnetic data 1957 indices K. and C. rapid variations / 
J. Bartel, A. Romana and J. Veldkamp ... [et al.] 
 - Amsterdam :  North Holland Publishing,  1961 
 - x, 281p. :  tables, diagrs. ;  25 cm. 
 - International union of geodesy and geophysics, Association of geomagnetism and aeronomy, IAGA Bulletin ;  121 .
<br/><br/> Published with financial assistance from UNESCO 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Magnetic materials<br/>Electric apparatus and appliances
<br/><br/><label>Dewey Class. No.: </label>538.74