@article{IM2_1995_45_3_a0,
     author = {A. V. Arutyunov},
     title = {On the theory of degenerate quadratic forms in the classical calculus of variations},
     journal = {Izvestiya. Mathematics },
     pages = {433--476},
     publisher = {mathdoc},
     volume = {45},
     number = {3},
     year = {1995},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1995_45_3_a0/}
}