Simultaneous radar and satellite observations of the polar cusp/cleft at Søndre Strømfjord Valladares, C. E. ; Basu, Su. ; Niciejewski, R. J. ; Sheehan, R. E. Abstract Publication: Electromagnetic Coupling in the Polar Clefts and Caps Pub Date: 1989 Bibcode: 1989ecpc.conf..285V