Mixed Finite Elements, Compatibility Conditions, and Applications [electronic resource] : Lectures given at the C.I.M.E. Summer School held in Cetraro, Italy June 26–July 1, 2006 / by Daniele Boffi, Franco Brezzi, Leszek F. Demkowicz, Ricardo G. Durán, Richard S. Falk, Michel Fortin ; edited by Daniele Boffi, Lucia Gastaldi.