@article{SJIM_2004_7_2_a3,
     author = {R. M. Garipov},
     title = {Classification up to isomorphism of crystallographic groups on {a~pseudo-Euclidean} plane. {III.~Lattices~}$*$. {Series~IX,~X}},
     journal = {Sibirskij \v{z}urnal industrialʹnoj matematiki},
     pages = {23--39},
     publisher = {mathdoc},
     volume = {7},
     number = {2},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SJIM_2004_7_2_a3/}
}