In Eqs. (23)–(32) of [1], ${ϵ}_{\infty }$ has to be replaced by ${ϵ}_0$. In Eq. (24), in the last element of the determinant $Q$, the factor $j_n(k_{\ell }R)$ has to be replaced by $j_n^{\prime }(k_{\ell }R)$. The sentence following Eq. (29) should read: “$Q$ is obtained from Eq. (24) by swapping the third and fourth rows of the determinant and then replacing the last three elements with the following expressions:”.