@article{DAN_1991_317_5_a4,
     author = {N. Yu. Kapustin and K. B. Sabitov},
     title = {On the solution of a problem in the theory of the {Frankl}   problem for equations of mixed type},
     journal = {Doklady Akademii Nauk},
     pages = {1048--1052},
     publisher = {mathdoc},
     volume = {317},
     number = {5},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_317_5_a4/}
}