@article{COCV_2002__7__309_0,
     author = {Raitums, Uldis},
     title = {Relaxation of quasilinear elliptic systems via {A-quasiconvex} envelopes},
     journal = {ESAIM: Control, Optimisation and Calculus of Variations},
     pages = {309--334},
     publisher = {EDP-Sciences},
     volume = {7},
     year = {2002},
     doi = {10.1051/cocv:2002014},
     mrnumber = {1925032},
     zbl = {1037.49011},
     language = {en},
     url = {http://archive.numdam.org/articles/10.1051/cocv:2002014/}
}