“…Since the characteristics of sources in practical problems are always unknown, there are many researches (Cannon and Duchateau, 1998;Fatullayev, 2004;Trong et al, 2005;Yan et al, 2008;Geng and Lin, 2009;Ahmadabadi et al, 2009;Tian et al, 2011;Liu et al, 2011) on such inverse problems of determining source terms from 1970s. In general, the unknown source cannot be obtained from practically restricted boundary measurements, completely.…”