@article{AA_2007_19_6_a9,
     author = {S. P. Khekalo},
     title = {Solution of the {Hadamard} problem in the class of stepwise gauge-equivalent deformations of homogeneous differential operators with constant coefficients},
     journal = {Algebra i analiz},
     pages = {200--219},
     year = {2007},
     volume = {19},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_2007_19_6_a9/}
}