@article{IM2_2004_68_3_a4,
     author = {S. V. Konyagin},
     title = {Problems on the set of squarefree numbers},
     journal = {Izvestiya. Mathematics },
     pages = {493--520},
     publisher = {mathdoc},
     volume = {68},
     number = {3},
     year = {2004},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2004_68_3_a4/}
}