@article{RM_1991_46_3_a16,
     author = {K. I. Tyurin},
     title = {Extremal properties of eigenvalues of the {Laplace} operator on a~ball},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {235--237},
     publisher = {mathdoc},
     volume = {46},
     number = {3},
     year = {1991},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1991_46_3_a16/}
}