@article{SM_1997_188_7_a5,
     author = {P. E. Zhidkov},
     title = {Completeness of systems of eigenfunctions for {the~Sturm--Liouville} operator with potential depending on the~spectral parameter and for one non-linear problem},
     journal = {Sbornik. Mathematics},
     pages = {1071--1084},
     publisher = {mathdoc},
     volume = {188},
     number = {7},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1997_188_7_a5/}
}