@article{ZNSL_2002_290_a7,
     author = {N. A. Shirokov},
     title = {Inverse approximation theorem on an infinite union of segments},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {168--176},
     publisher = {mathdoc},
     volume = {290},
     year = {2002},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2002_290_a7/}
}