@article{EJDE_2013__2013__a4,
     author = {Goriunov, Andrii and Mikhailets, Vladimir and Pankrashkin, Konstantin},
     title = {Formally self-adjoint quasi-differential operators and boundary-value problems},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {2013},
     year = {2013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2013__2013__a4/}
}