@article{MO_2015_4_a4,
     author = {T. A. Ehrenfest-Afanassjewa},
     title = {Exercises in experimental geometry,},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {59--71},
     year = {2015},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_2015_4_a4/}
}