An asteroseismic test of diffusion theory in white dwarfs T. S. Metcalfe, R. E. Nather, T. K. Watson, S.-L. Kim, B.-G. Park and G. Handler A&A, 435 2 (2005) 649-655 Published online: 29 April 2005 DOI: 10.1051/0004-6361:20042608