This article has been retracted: please see Elsevier policy on article withdrawal (https://www.elsevier.com/about/policies-and-standards/article-withdrawal).
This article has been retracted at the request of the Editor.
An investigation conducted on behalf of the journal by Elsevier's Research Integrity & Publishing Ethics team found a significant increase of citations to papers published by the author, Abdulla - Al Kafy, between the original submission and the revised version of this article. In summary, four papers by the author were cited in the original version of the article. This increased to twenty-one papers in the revised version of the article.
The Editor has lost confidence in the findings of the article and has determined that it should be retracted.
The authors disagree with the retraction and dispute the grounds for it.