@article{DAN_1966_168_6_a2,
     author = {I. M. Gel'fand and M. I. Graev and Z. Ya. Shapiro},
     title = {Integral geometry on manifolds of $k$-dimensional planes},
     journal = {Doklady Akademii Nauk},
     pages = {1236--1238},
     publisher = {mathdoc},
     volume = {168},
     number = {6},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1966_168_6_a2/}
}