Confirmation of two cyclotron lines in Vela X-1 I. Kreykenbohm, W. Coburn, J. Wilms, P. Kretschmar, R. Staubert, W. A. Heindl and R. E. Rothschild A&A, 395 1 (2002) 129-140 Published online: 29 October 2002 DOI: 10.1051/0004-6361:20021181