@article{MO_1997_1_a3,
     author = {S. A. Dorichenko},
     title = {An optional course in mathematics as a set of sheets},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {38--75},
     year = {1997},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_1997_1_a3/}
}