@article{DAN_1957_117_5_a6,
     author = {V. G. Lemlein},
     title = {The curvature tensor and certain types of spaces of symmetric, nearly symplectic connectivity},
     journal = {Doklady Akademii Nauk},
     pages = {755--758},
     publisher = {mathdoc},
     volume = {117},
     number = {5},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_117_5_a6/}
}