Xilong Sun Anxi Yu Zhen Dong Diannong Liang Research on differential interferometry for spaceborne bistatic SAR. 2118-2121 2007 IGARSS http://dx.doi.org/10.1109/IGARSS.2007.4423252 conf/igarss/2007 db/conf/igarss/igarss2007.html#SunYDL07