@article{JIS_2011__14_8_a7,
     author = {Chen, Shiqin and Zhai, Wenguang},
     title = {Reciprocals of the gcd-sum functions},
     journal = {Journal of integer sequences},
     publisher = {mathdoc},
     volume = {14},
     number = {8},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2011__14_8_a7/}
}