@article{AA_2010_22_5_a0,
     author = {A. V. Badanin and E. L. Korotyaev},
     title = {Spectral estimates for a~periodic fourth-order operator},
     journal = {Algebra i analiz},
     pages = {1--48},
     publisher = {mathdoc},
     volume = {22},
     number = {5},
     year = {2010},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_2010_22_5_a0/}
}