@article{DAN_1970_193_5_a5,
     author = {Yu. I. Kulakov},
     title = {The geometry of spaces of constant curvature as a special case of the theory of physical structures},
     journal = {Doklady Akademii Nauk},
     pages = {985--987},
     publisher = {mathdoc},
     volume = {193},
     number = {5},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_193_5_a5/}
}