@article {Zisler2016, title = {Non-Binary Discrete Tomography by Continuous Non-Convex Optimization}, journal = {IEEE Comp. Imaging}, volume = {2}, number = {3}, year = {2016}, pages = {335-347}, author = {M. Zisler and Kappes, J.H. and Schn{\"o}rr, Cl. and Petra, S. and Christoph Schn{\"o}rr} }