no. 3
Diophantine approximation by square-free numbers
Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Série 4, Tome 11 (1984) no. 3, pp. 353-359. 
@article{ASNSP_1984_4_11_3_353_0,
     author = {Balog, A. and Perelli, Alberto},
     title = {Diophantine approximation by square-free numbers},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {353--359},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 11},
     number = {3},
     year = {1984},
     zbl = {0565.10029},
     mrnumber = {785616},
     language = {en},
     url = {www.numdam.org/item/ASNSP_1984_4_11_3_353_0/}
}
Balog, A.; Perelli, A. Diophantine approximation by square-free numbers. Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Série 4, Tome 11 (1984) no. 3, pp. 353-359. http://www.numdam.org/item/ASNSP_1984_4_11_3_353_0/

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