Andreas Klein, Markus Wessler. Extended visual cryptography schemes. Inf. Comput., 205(5):716-732, 2007. [doi]
@article{KleinW07, title = {Extended visual cryptography schemes}, author = {Andreas Klein and Markus Wessler}, year = {2007}, doi = {10.1016/j.ic.2006.12.005}, url = {http://dx.doi.org/10.1016/j.ic.2006.12.005}, researchr = {https://researchr.org/publication/KleinW07}, cites = {0}, citedby = {0}, journal = {Inf. Comput.}, volume = {205}, number = {5}, pages = {716-732}, }