@article{RM_1979_34_6_a1, author = {P. S. Aleksandrov}, title = {Introductory remarks}, journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova}, pages = {11--13}, publisher = {mathdoc}, volume = {34}, number = {6}, year = {1979}, language = {en}, url = {http://geodesic.mathdoc.fr/item/RM_1979_34_6_a1/} }