@article{RM_1962_17_2_a1,
     author = {A. M. Zverkin and G. A. Kamenskii and S. B. Norkin and L. \`E. \`El'sgol'ts},
     title = {Differential equations with a~perturbed argument},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {61--146},
     publisher = {mathdoc},
     volume = {17},
     number = {2},
     year = {1962},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1962_17_2_a1/}
}