Editorial Expression of Concern: J Inequal Appl 2015, 273 (2015). https://doi.org/10.1186/s13660-015-0792-3.

The Editors-in-Chief are issuing this editorial Expression of Concern to alert readers that the first paragraph in the Introduction of this article [1] contains some text that is identical with that in the first paragraph of the Introduction of a previous article by Gasull and Utzet [2]. Zhen-Hang Yang and Yu-Ming Chu have not responded to correspondence about this notice.