@article{MO_2013_4_a4,
     author = {A. Ya. Belov and N. S. Kellin},
     title = {What a rigorous proof should be like?},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {70--85},
     year = {2013},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_2013_4_a4/}
}