@article{MABA_1994_8_4_a1,
     author = {SvetIa Spirova},
     title = {Strong {Solvability} of a {Boundary} {Value} {Problem} for an {Equation} of {Mixed} {Type}},
     journal = {Mathematica balkanica},
     pages = {287},
     year = {1994},
     volume = {8},
     number = {4},
     url = {http://geodesic.mathdoc.fr/item/MABA_1994_8_4_a1/}
}