“…In ref. [24], the results obtained by the Borel-Padé summation and Leaver's method [29] were compared and the consistency of the two methods was determined. Here we can see, e.g from Table 1, that the values obtained by the Borel-Padé summation agrees well with that by the WKB-Padé method when the refractive index is not less than 5 and l is greater than n. For example, we take two sets of data, (η = 5, l = 3, n = 3) and (η = 15, l = 3, n = 0), respectively, and find that the two real parts, 1.179851 and 1.203996 in the first set, differ by 2.01%, and 1.319595 and 1.319663 in the second set, just by 0.07%.…”