%0 Journal Article %A Braess, Dietrich %A Hoppe, R.H.W. %A Linsenmann, Christopher %T A two-energies principle for the biharmonic equation and an a posteriori error estimator for an interior penalty discontinuous Galerkin approximation %J ESAIM: Mathematical Modelling and Numerical Analysis %D 2018 %P 2479-2504 %V 52 %N 6 %I EDP-Sciences %U http://www.numdam.org/articles/10.1051/m2an/2016074/ %R 10.1051/m2an/2016074 %G en %F M2AN_2018__52_6_2479_0