@article{KJM_2005_27_1_a4,
     author = {Milorad R. Stevanovi\'c},
     title = {Sequences related to the sum of divisors},
     journal = {Kragujevac Journal of Mathematics},
     pages = {47 - 54},
     publisher = {mathdoc},
     volume = {27},
     number = {1},
     year = {2005},
     zbl = {1082.11059},
     url = {http://geodesic.mathdoc.fr/item/KJM_2005_27_1_a4/}
}