Pierre Poulin, John Amanatides. Shading and shadowing with linear light sources. Computers & Graphics, 15(2):259-265, 1991. [doi]
@article{PoulinA91,
title = {Shading and shadowing with linear light sources},
author = {Pierre Poulin and John Amanatides},
year = {1991},
doi = {10.1016/0097-8493(91)90079-W},
url = {http://dx.doi.org/10.1016/0097-8493(91)90079-W},
tags = {source-to-source, open-source},
researchr = {https://researchr.org/publication/PoulinA91},
cites = {0},
citedby = {0},
journal = {Computers & Graphics},
volume = {15},
number = {2},
pages = {259-265},
}