@article{10_1017_S001708950000673X,
     author = {Foster, D. M. E.},
     title = {Estimates for a remainder term associated with the sum of digits function},
     journal = {Glasgow mathematical journal},
     pages = {109--129},
     year = {1987},
     volume = {29},
     number = {1},
     doi = {10.1017/S001708950000673X},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S001708950000673X/}
}