@article{CGMW2010 , author = {Markus Chimani and Carsten Gutwenger and Petra Mutzel and Hoi-Ming Wong} , title = {Layer-Free Upward Crossing Minimization} , journal = {ACM Journal of Experimental Algorithmics} , volume = {15} , year = {2010} , pages = {2.2:1--2.2:27} , doi = {10.1145/1671970.1671975} }