This article has been retracted: please see Elsevier Policy on Article Withdrawal ( https://www.elsevier.com/about/policies/article-withdrawal ).

This article has been retracted at the request of the Editors-in-Chief because the author has disclosed a serious ethical breach. The article has plagiarized previously published works in Vietnam: http://www.sieuamvietnam.vn/cls-xhns-thai-ky and http://www.sieuamvietnam.vn/hoi-chung-joubert-bao-cao-ca-va-hoi-cuu-y-van . One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter.

The author fully recognizes the severity of this issue and the ethical breach it represents as well as the necessity of addressing this matter transparently. The author offers apologies to the readers of the journal.