@article{MZM_2009_85_5_a3,
     author = {O. A. Veliev and A. A. Shkalikov},
     title = {On the {Riesz} {Basis} {Property} of the {Eigen-} and {Associated} {Functions} of {Periodic} and {Antiperiodic} {Sturm--Liouville} {Problems}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {671--686},
     publisher = {mathdoc},
     volume = {85},
     number = {5},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2009_85_5_a3/}
}