RETRACTED: Pancyclic graphs and degree sum and neighborhood union involving distance two

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editor-in-Chief.The original submission was made without the approval of the two previously listed co-authors Ping Zhang and Yu-Jong Tzeng, who neither contributed to the research nor agreed with corresponding author Kewen Zhao to have a paper submitted in their names. This represents a clear violation of our policies on authorship which state “Authorship should be limited to those who have made a significant contribution to the conception, design, execution, or interpretation of the reported study... The corresponding author should ensure that all appropriate co-authors and no inappropriate co-authors are included on the paper, and that all co-authors have seen and approved the final version of the paper and have agreed to its submission for publication.”