δ Sct-type nature of the variable V2109 Cyg E. Rodríguez, A. Arellano Ferro, V. Costa, M. J. López-González and J. P. Sareyan A&A, 407 3 (2003) 1059-1065 Published online: 17 November 2003 DOI: 10.1051/0004-6361:20030925