@article{FAA_1986_20_3_a5,
     author = {Yu. V. Chekanov},
     title = {Caustics in geometrical optics},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {66--69},
     publisher = {mathdoc},
     volume = {20},
     number = {3},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1986_20_3_a5/}
}