Leonardo Campagnolo and Waldemar Celes. 2019.
 Interactive directional ambient occlusion and shadow computations for volume ray casting. In <em>Proceedings of the 32th Conference on Graphics, Patterns and Images</em>, October 28, 2019, Rio de Janeiro, Brasil. SBC, Porto Alegre, Brasil. DOI: <a href="https://doi.org/10.5753/sibgrapi.2019.9819">https://doi.org/10.5753/sibgrapi.2019.9819</a>.