@article{RM_1984_39_2_a9,
     author = {Yu. V. Egorov and V. A. Kondrat'ev},
     title = {On~estimates of the first eigenvalue of the {Sturm--Liouville} problem},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {149--150},
     publisher = {mathdoc},
     volume = {39},
     number = {2},
     year = {1984},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1984_39_2_a9/}
}