Evidence for CO depletion in the inner regions of gas-rich protoplanetary disks G. van der Plas, M. E. van den Ancker, B. Acke, A. Carmona, C. Dominik, D. Fedele and L. B. F. M. Waters A&A, 500 3 (2009) 1137-1141 Published online: 29 April 2009 DOI: 10.1051/0004-6361/200811148