@article{ZNSL_1980_102_a0,
     author = {Yu. K. Dem'yanovich},
     title = {On the evaluation of truncation error of the projection methods in the problem of best approximation},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {5--18},
     publisher = {mathdoc},
     volume = {102},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1980_102_a0/}
}