@article{ZNSL_2011_396_a6,
     author = {I. A. Ibragimov},
     title = {Low bounds for risk functions in non-parametric estimation problems},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {102--110},
     publisher = {mathdoc},
     volume = {396},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2011_396_a6/}
}