TThe authors correct part of the proof of Theorems 4.1 and 4.2 in the above-titled paper 1, in order to avoid the use of the estimate E(t) ? 1 ? 1/E(t) ? 1 which is not justified since E(t) ? (0,?), while the idea remained the same. The authors apologize for any inconvenience that may have been caused.
Jovanović et al. (Wed,) studied this question.