Opacity in the upper atmospheres of active stars - II. AD Leonis D. J. Christian, M. Mathioudakis, D. S. Bloomfield, J. Dupuis, F. P. Keenan, D. L. Pollacco and R. F. Malina A&A, 454 3 (2006) 889-894 Published online: 17 July 2006 DOI: 10.1051/0004-6361:20054404