@article{IM2_1969_3_4_a4,
     author = {R. V. Gamkrelidze and G. L. Kharatishvili},
     title = {Extremal problems in linear topological spaces},
     journal = {Izvestiya. Mathematics },
     pages = {737--794},
     publisher = {mathdoc},
     volume = {3},
     number = {4},
     year = {1969},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1969_3_4_a4/}
}