@article{DAN_1958_122_5_a1,
     author = {M. M. Vainberg and Ya. L. \`Engel'son},
     title = {On the square root of a linear operator in locally convex spaces},
     journal = {Doklady Akademii Nauk},
     pages = {755--758},
     publisher = {mathdoc},
     volume = {122},
     number = {5},
     year = {1958},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1958_122_5_a1/}
}