equation icon  ( ) guu = - f 1 + r2fE* + O(r3/R3), (568) ( ) gua = - _O_a + 2r2f E*a + B*a + O(r3/R3), (569) 3 ( ) 1-2 m2- * 1- 2 * 3 3 gab = dab- _O_a_O_b - 3r 1 - 2 r2 E ab- 3 r Bab + O(r /R ), (570)