Simeon Ball, András Gács, Péter Sziklai. On the number of directions determined by a pair of functions over a prime field. Journal of Combinatorial Theory, Series A, 115(3):505-516, 2008. [doi]
@article{BallGS08,
title = {On the number of directions determined by a pair of functions over a prime field},
author = {Simeon Ball and András Gács and Péter Sziklai},
year = {2008},
doi = {10.1016/j.jcta.2007.08.001},
url = {http://dx.doi.org/10.1016/j.jcta.2007.08.001},
researchr = {https://researchr.org/publication/BallGS08},
cites = {0},
citedby = {0},
journal = {Journal of Combinatorial Theory, Series A},
volume = {115},
number = {3},
pages = {505-516},
}