@article{VMJ_2001_3_4_a1,
     author = {V. A. Eleev and V. N. Lesev},
     title = {On two boundary value problems for mixed equations with perpendicular lines of type change},
     journal = {Vladikavkazskij matemati\v{c}eskij \v{z}urnal},
     pages = {9--22},
     publisher = {mathdoc},
     volume = {3},
     number = {4},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMJ_2001_3_4_a1/}
}