@article{10_4153_CMB_2002_013_9,
     author = {Luca, Florian},
     title = {The {Number} of {Non-Zero} {Digits} of n!},
     journal = {Canadian mathematical bulletin},
     pages = {115--118},
     year = {2002},
     volume = {45},
     number = {1},
     doi = {10.4153/CMB-2002-013-9},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-2002-013-9/}
}