Pulsations of massive ZZ Ceti stars with carbon/oxygen and oxygen/neon cores A. H. Córsico, E. García-Berro, L. G. Althaus and J. Isern A&A, 427 3 (2004) 923-932 Published online: 16 November 2004 DOI: 10.1051/0004-6361:20040416