@article{CRMATH_2003__336_1_11_0,
     author = {Bevan, Jonathan},
     title = {An example of a {\protect\emph{C}\protect\textsuperscript{1,1}} polyconvex function with no differentiable convex representative},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {11--14},
     publisher = {Elsevier},
     volume = {336},
     number = {1},
     year = {2003},
     doi = {10.1016/S1631-073X(02)00015-8},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/S1631-073X(02)00015-8/}
}