1. Centre for Business Mathematics and Informatics, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa
2. Independent Researcher, 116 Cockspur Road, Roodepoort 1709, South Africa
3. Independent Researcher, P.O. Box 613 Heliopolis, Cairo 11757, Egypt
4. Independent Researcher, 108 Bateleur Str., Midrand 1628, South Africa
5. National Institute for Theoretical and Computational Sciences (NITheCS), Pretoria 0001, South Africa
6. Independent Researcher, DLF Cyber City, Gurgaon 122002, India