@article{MM2_1991__72_1_155639,
     author = {Gerald Kuba},
     title = {A mean value theorem on differences of two k-th powers of numbers in residue classes.},
     journal = {Manuscripta mathematica},
     pages = {213--222},
     year = {1991},
     volume = {72},
     number = {1},
     zbl = {0735.11047},
     url = {http://geodesic.mathdoc.fr/item/MM2_1991__72_1_155639/}
}