@article{SJIM_2003_6_4_a1,
     author = {R. M. Garipov},
     title = {Classification up to isomorphism of crystallographic groups on {a~pseudo-Euclidean} plane. {I.~The} general case},
     journal = {Sibirskij \v{z}urnal industrialʹnoj matematiki},
     pages = {11--31},
     publisher = {mathdoc},
     volume = {6},
     number = {4},
     year = {2003},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SJIM_2003_6_4_a1/}
}