“…C.ah C de fc bg/sz 2 C.ad bc/z 2 C .eh fg/s 2 z 2 (27) To find the initial conditions, let H P .s, z/ D a 0 C a 1 z C a 2 sz C a 3 sz 2 : : :, and multiply both sides of Equation (27) by its denominator, then equate the coefficients of each indeterminates s, z. As we will allow for a negative index in the recurrence relation, the condition P.m, n/ D 0 for m, n < 0 must hold, and only a 0 , a 1 and a 2 are required for the initial conditions [26] as a 3 , a 4 , : : : can be obtained from the recursion.…”