[1] Ton Duc Thang Univ, Fac Math & Stat, Appl Anal Res Grp, Ho Chi Minh City, Vietnam
[2] Thu Dau Mot Univ, Div Appl Math, Thu Dau Mot, Binh Duong Prov, Vietnam
[3] Cankaya Univ, Dept Math, Ankara, Turkey
[4] China Med Univ, China Med Univ Hosp, Dept Med Res, Taichung, Taiwan
[5] Inst Space Sci, Magurele, Romania