John Karro James P. Cohoon A Spiffy Tool for the Simultaneous Placement and Global Routing for Three-Dimensional Field-Programmable Gate Arrays. 230-231 1999 conf/glvlsi/1999 Great Lakes Symposium on VLSI http://csdl.computer.org/comp/proceedings/glsvlsi/1999/0104/00/01040230abs.htm db/conf/glvlsi/glvlsi1999.html#KarroC99