Magnetic Doppler imaging of 53 Camelopardalis in all four Stokes parameters O. Kochukhov, S. Bagnulo, G. A. Wade, L. Sangalli, N. Piskunov, J. D. Landstreet, P. Petit and T. A. A. Sigut A&A, 414 2 (2004) 613-632 Published online: 19 January 2004 DOI: 10.1051/0004-6361:20031595