We consider a class of fourth order elliptic systems which include the Euler-Lagrange equations of biharmonic mappings in dimension 4 and we prove that a weak limit of weak solutions to such systems is again a weak solution to a limit system.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm214-2-3, author = {Pawe\l\ Goldstein and Pawe\l\ Strzelecki and Anna Zatorska-Goldstein}, title = {Weak compactness of solutions for fourth order elliptic systems with critical growth}, journal = {Studia Mathematica}, volume = {215}, year = {2013}, pages = {137-156}, zbl = {1277.35163}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm214-2-3} }
Paweł Goldstein; Paweł Strzelecki; Anna Zatorska-Goldstein. Weak compactness of solutions for fourth order elliptic systems with critical growth. Studia Mathematica, Tome 215 (2013) pp. 137-156. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm214-2-3/