@article{SM_1990_67_1_a2,
     author = {D. \`E. Allakhverdiev and A. M. Akhmedov},
     title = {Some classes of generalized spectral operators and their applications},
     journal = {Sbornik. Mathematics},
     pages = {43--63},
     publisher = {mathdoc},
     volume = {67},
     number = {1},
     year = {1990},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1990_67_1_a2/}
}