@article{SM_1975_26_3_a6,
     author = {S. A. Laptev},
     title = {On~the behaviour for large values of the time of the solution of the {Cauchy} problem for the equation $\frac{\partial^2u}{\partial t^2}-\frac{\partial^2u}{\partial x^2}+\alpha(x)u=0$},
     journal = {Sbornik. Mathematics},
     pages = {403--426},
     publisher = {mathdoc},
     volume = {26},
     number = {3},
     year = {1975},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1975_26_3_a6/}
}