Thomas W.H. Lui, The Hong Kong Polytechnic University
3 July 2015
This comment is to correct an error in formula (6) of the paper. An errata file can be found from following link (https://docs.google.com/document/d/1hhVDlKyqUrA10qYKiJcY2ecFgP6K1ophvXfH6b65x2E/edit?pref=2&pli=1). This is a typographical error and does not change the results or conclusion of the paper. We apologize for any inconvenience.
Correction in formula (6)
3 July 2015
This comment is to correct an error in formula (6) of the paper. An errata file can be found from following link (https://docs.google.com/document/d/1hhVDlKyqUrA10qYKiJcY2ecFgP6K1ophvXfH6b65x2E/edit?pref=2&pli=1). This is a typographical error and does not change the results or conclusion of the paper. We apologize for any inconvenience.Competing interests
None declared