@article{VMUMM_2004_6_a9,
     author = {V. V. Fedorchuk and V. A. Chatyrko},
     title = {On a question of de {Groot}},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {50--52},
     publisher = {mathdoc},
     number = {6},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2004_6_a9/}
}