@article{TM_1978_148_a12,
     author = {B. N. Delone and N. P. Dolbilin and M. I. Shtogrin},
     title = {Combinatorial and metric theory of planigons},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {109--140},
     publisher = {mathdoc},
     volume = {148},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1978_148_a12/}
}