Yachyang Sun Ting-Chi Wang Chak-Kuen Wong C. L. Liu Routing for symmetric FPGAs and FPICs. 20-31 1997 16 IEEE Trans. on CAD of Integrated Circuits and Systems 1 http://doi.ieeecomputersociety.org/10.1109/43.559329 db/journals/tcad/tcad16.html#SunWWL97