[Zhou, Shuang-Shuang] Hunan City Univ, Coll Sci, Yiyang 413000, Peoples R China.
[Almarashi, Adel] Jazan Univ, Coll Sci, Dept Math, Post Box 2097,New Campus, Jazan, Saudi Arabia.
[Dara, Rebwar Nasir] Salahaddin Univ Erbil, Coll Sci, Dept Geol, Erbil, Iraq.
[Dara, Rebwar Nasir] Knowledge Univ, Coll Engn, Dept Petr Engn, Erbil, Kurdistan Regio, Iraq.
[Issakhov, Alibek] Al Farabi Kazakh Natl Univ, Dept Math & Comp Modeling, Alma Ata, Kazakhstan.