The operator of fractional integration is defined as _a D_t^(-ν) f(t) = 1/(Γ(ν)) integral_a^t f(u)(t - u)^(ν - 1) d u for ν>0 with _a D_t^0 f(t) = f(t) (Oldham and Spanier 1974, Miller and Ross 1993, Srivastava and Saxena 2001, Saxena 2002).