Yang Yi Peng Li Vivek Sarin Weiping Shi A Preconditioned Hierarchical Algorithm for Impedance Extraction of Three-Dimensional Structures With Multiple Dielectrics. 1918-1927 2008 27 IEEE Trans. on CAD of Integrated Circuits and Systems 11 http://dx.doi.org/10.1109/TCAD.2008.2006089 db/journals/tcad/tcad27.html#YiLSS08