@article{ASNSP_1999_4_28_4_591_0,
     author = {Br\"udern, J\"org and Perelli, Alberto},
     title = {Exponential sums and additive problems involving square-free numbers},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {591--613},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 28},
     number = {4},
     year = {1999},
     mrnumber = {1760532},
     zbl = {1019.11028},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1999_4_28_4_591_0/}
}