Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{MS_1964__106_4_a2, author = {{\CYRV}.{\CYREREV}. {\CYRL}{\cyrya}{\cyrn}{\cyrc}{\cyre}}, title = {A differential operator with spectral singularities. {I}}, journal = {Matemati\v{c}eskij sbornik}, pages = {521--561}, publisher = {mathdoc}, volume = {106}, number = {4}, year = {1964}, zbl = {0189.38102}, language = {en}, url = {http://geodesic.mathdoc.fr/item/MS_1964__106_4_a2/} }
В.Э. Лянце. A differential operator with spectral singularities. I. Matematičeskij sbornik, Tome 106 (1964) no. 4, pp. 521-561. http://geodesic.mathdoc.fr/item/MS_1964__106_4_a2/