@article{AA_2015_27_5_a4,
     author = {D. M. Polyakov},
     title = {Spectral analysis of a~fourth order differential operator with periodic and antiperiodic boundary conditions},
     journal = {Algebra i analiz},
     pages = {117--152},
     publisher = {mathdoc},
     volume = {27},
     number = {5},
     year = {2015},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_2015_27_5_a4/}
}