@article{VUU_2008_2_a49,
     author = {A. L. Teptin},
     title = {On the sign of the {Green's} function of a~boundary value problem with periodic and {Sturm's} boundary conditions},
     journal = {Vestnik Udmurtskogo universiteta. Matematika, mehanika, kompʹ\^uternye nauki},
     pages = {150--151},
     publisher = {mathdoc},
     number = {2},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VUU_2008_2_a49/}
}