@article{FPM_2006_12_6_a5,
     author = {P. A. Zakharchenko and E. V. Radkevich},
     title = {On the well-posedness of the mixed problem for hyperbolic operators with characteristics of variable multiplicity},
     journal = {Fundamentalʹna\^a i prikladna\^a matematika},
     pages = {85--98},
     publisher = {mathdoc},
     volume = {12},
     number = {6},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FPM_2006_12_6_a5/}
}