@article{IM2_1967_1_5_a11,
     author = {Ya. I. Zhitomirskii},
     title = {Uniqueness classes for solutions of the {Cauchy} problem for linear},
     journal = {Izvestiya. Mathematics},
     pages = {1109--1129},
     year = {1967},
     volume = {1},
     number = {5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1967_1_5_a11/}
}