@Article{ dacmar99, author = { Dacorogna, Bernard and Marcellini, Paolo }, title = { Attainment of minima and implicit partial differential equations }, journal = { Ricerche di Matematica }, year = { 1999 }, volume = { 48 }, pages = { 311-346 }, URL = { http://cvgmt.sns.it/paper/651/ }, note = { cvgmt preprint} }