@article{10_4064_aa123_4_6,
     author = {Youssef Fares},
     title = {$\delta $-rings and factorial sequences preservation},
     journal = {Acta Arithmetica},
     pages = {377--388},
     publisher = {mathdoc},
     volume = {123},
     number = {4},
     year = {2006},
     doi = {10.4064/aa123-4-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa123-4-6/}
}