On the cyclotron line in Cepheus X-4 V. A. McBride, J. Wilms, I. Kreykenbohm, M. J. Coe, R. E. Rothschild, P. Kretschmar, K. Pottschmidt, J. Fisher and T. Hamson A&A, 470 3 (2007) 1065-1070 Published online: 25 May 2007 DOI: 10.1051/0004-6361:20077238