Andrew B. Kahng Paul Tucker Alexander Zelikovsky Optimization of Linear Placements for Wirelength Minimization with Free Sites. 241-244 1999 conf/aspdac/1999 ASP-DAC http://doi.ieeecomputersociety.org/10.1109/ASPDAC.1999.760005 db/conf/aspdac/aspdac1999.html#KahngTZ99