@article{ZNSL_2001_280_a9,
     author = {D. V. Ivanov and S. E. Kozlov},
     title = {Classification of totally geodesic surfaces in the manifold of directions in physical space},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {163--172},
     year = {2001},
     volume = {280},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2001_280_a9/}
}