Influence of turbulence on the shape of a spectral line - The analytical approach N. A. Silant'ev, E. E. Lekht, J. E. Mendoza-Torres and G. M. Rudnitskij A&A, 453 3 (2006) 989-1002 Published online: 28 June 2006 DOI: 10.1051/0004-6361:20053069