equation icon  integral u- ( 1 ' ) htaai'bl'(x') = 4m G+a'b'mn- -ga'b'G +dd'mn (x',z)umun dt, (587) - oo ( 2 ) tail ' integral u- 1 d' ' m n ha'b'g'(x ) = 4m \~/ g' G+a'b'mn - --ga'b'G + d'mn (x ,z)u u dt (588) - oo 2