@article{DE_1999_35_4_a11,
     author = {A. N. Bobrov},
     title = {The trace of the {Laplace{\textendash}Beltrami} operator with a potential on a {Zoll} surface},
     journal = {Differencialʹnye uravneni\^a},
     pages = {528--539},
     year = {1999},
     volume = {35},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1999_35_4_a11/}
}