@article{MO_2009_1_a3,
     author = {I. P. Kostenko},
     title = {Laws of {Understandable} {Educational} {Text}},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {27--33},
     year = {2009},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_2009_1_a3/}
}