@article{MZM_1976_20_6_a8,
     author = {M. S. Eremin},
     title = {Eigenfunctions and associated functions of an $n$-th-order linear differential operator},
     journal = {Matemati\v{c}eskie zametki},
     pages = {869--878},
     publisher = {mathdoc},
     volume = {20},
     number = {6},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1976_20_6_a8/}
}