deletions | additions       diff --git a/bibliography/biblio.bib b/bibliography/biblio.bib  index 4ffc25c..4d050d9 100644  --- a/bibliography/biblio.bib  +++ b/bibliography/biblio.bib 
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}  @inproceedings@inproceedings{litsphere-gi2001, @inproceedings{litsphere-gi2001,  title = {The {{The  Lit Sphere: A Model for Capturing NPR Shading from Art}, Art}},  author = {Peter-Pike Sloan and William Martin and Amy Gooch and Bruce Gooch}, booktitle = {Proceedings of the Graphics Interface 2001 Conference, June 7-9 2001, Ottawa, Ontario, Canada}, url = {http://graphicsinterface.org/wp-content/uploads/gi2001-17.pdf}, year = {2001}, month = {June}, pages = {143--150} {143--150},  }  @article{Bruckner_2007,  doi = {10.1111/j.1467-8659.2007.01095.x},  url = {http://dx.doi.org/10.1111/j.1467-8659.2007.01095.x},  year = {2007},  month = {sep},  publisher = {Wiley-Blackwell},  volume = {26},  number = {3},  pages = {715--724},  author = {S. Bruckner and M. E. Gröller},  title = {{Style Transfer Functions for Illustrative Volume Rendering}},  journal = {Computer Graphics Forum},  }