@article{UFA_2015_7_3_a1,
     author = {N. F. Valeev and E. A. Nazirova and Ya. T. Sultanaev},
     title = {On a~new approach for studying asymptotic behavior of solutions to singular differential equations},
     journal = {Ufa mathematical journal},
     pages = {9--14},
     publisher = {mathdoc},
     volume = {7},
     number = {3},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UFA_2015_7_3_a1/}
}