@article{VMUMM_1987_6_a0,
     author = {O. A. Kruzhalov},
     title = {An example of a quasiconvex but not polyconvex function},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {3--6},
     publisher = {mathdoc},
     number = {6},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1987_6_a0/}
}