Correction of quasi-static wavefront errors for ELT with two sequential DMs L. Pueyo, S. B Shaklan, A. Give’on, M. Troy, N. Jeremy Kasdin, J. Kay, T. Groff, M. McElwain and R. Soummer Published online: 24 February 2010 DOI: 10.1051/ao4elt/201005009