The helium-weak silicon star HR 7224 - I. Radial velocity and line profile variations H. Lehmann, V. Tsymbal, D. E. Mkrtichian and L. Fraga A&A, 457 3 (2006) 1033-1041 Published online: 12 September 2006 DOI: 10.1051/0004-6361:20065508