@article{JIS_2014__17_9_a2,
     author = {Broughan, Kevin A. and Zhou, Qizhi},
     title = {On the ratio of the sum of divisors and {Euler's} totient function. {II.}},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {17},
     number = {9},
     year = {2014},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2014__17_9_a2/}
}