@article{702183,
     title = {Some new problems in the theory of partial differential equations},
     booktitle = {Differential Equations and Their Applications},
     series = {GDML\_Books},
     publisher = {Publishing House of the Czechoslovak Academy of Sciences},
     address = {Prague},
     year = {1963},
     pages = {167-177},
     mrnumber = {MR0169392},
     zbl = {0161.08603},
     url = {http://dml.mathdoc.fr/item/702183}
}

Sobolev, S. L. Some new problems in the theory of partial differential equations, dans Differential Equations and Their Applications, GDML_Books,  (1963), pp. 167-177. http://gdmltest.u-ga.fr/item/702183/