@article{DAN_1967_173_5_a0,
     author = {B. N. Delone and S. S. Ryshkov},
     title = {A contribution to the theory of the extrema of a multi-dimensional $\zeta$-function},
     journal = {Doklady Akademii Nauk},
     pages = {991--994},
     publisher = {mathdoc},
     volume = {173},
     number = {5},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_173_5_a0/}
}