@article{RM_1996_51_1_a23,
     author = {Ya. B. Vorobets},
     title = {Planar structures and billiards in rational polygons},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {177--178},
     publisher = {mathdoc},
     volume = {51},
     number = {1},
     year = {1996},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1996_51_1_a23/}
}