@article{MZM_2003_74_1_a14,
     author = {I. M. Karabash and A. S. Kostenko},
     title = {Similarity of $\operatorname{sgn}x\bigl(-\frac{d^2}{dx^2}+c\delta\bigr)$ {Type} {Operators} to {Normal} and {Self-adjoint} {Operators}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {134--139},
     publisher = {mathdoc},
     volume = {74},
     number = {1},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2003_74_1_a14/}
}