Fast characteristic basis functions construction procedure
 based on the PO and EEC method
HOU Zhao-guo, WANG Chao2, DONG Chun-zhu, YIN Hong-cheng
Journal of Systems Engineering and Electronics . 2011, (7): 1458 -1461 .  DOI: 10.3969/j.issn.1001-506X.2011.07.06