1. Karatas District, 400 St., Nizamkent Apartments, Bldg. B, No. 24, Sahinbey, Gaziantep 27470, Turkey (corresponding author).
2. Karatas District, 429 St., Haskent 4 Apartments, Bldg. C, No. 34, Sahinbey, Gaziantep 27470, Turkey.
3. Dept. of Mathematics and Statistics, American Univ. of the Middle East, Egaila 54200, Kuwait.