@article{GDZPPN002185385,
title = {The distribution of r-th powers in a finite field.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {244},
year = {1970},
pages = {183-187},
zbl = {0205.35504},
url = {http://dml.mathdoc.fr/item/GDZPPN002185385}
}
Whyburn, Clifton. The distribution of r-th powers in a finite field.. Journal für die reine und angewandte Mathematik, Tome 244 (1970) pp. 183-187. http://gdmltest.u-ga.fr/item/GDZPPN002185385/