The error in subcase k = 2 j + 1 with sj < 0 can be traced back to the statement Since this term is independent of a µ , we get . . . . just above the Eqn. (48'). This statement is not correct since ϵ in fact does depend on a µ ; however, this dependence got lost when replacing the limit η → ∞ with a different limit ϵ → 1 in Eqn. (31'). Consequently Eqn. (48') has a limit different from 0. To derive the correct limit, we have to go back to Eqn. (31') and repeat the derivation for case 2b, while keeping track of a µ in the integration limits.