@article{JIS_2009__12_6_a6,
     author = {Deng, Moujie},
     title = {A note on perfect totient numbers},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {12},
     number = {6},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2009__12_6_a6/}
}