@article{SM_2000_191_10_a8,
     author = {V. A. Yurko},
     title = {An inverse problem for differential operator pencils},
     journal = {Sbornik. Mathematics},
     pages = {1561--1586},
     year = {2000},
     volume = {191},
     number = {10},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2000_191_10_a8/}
}