1. Department of Allied Sciences, Graphic Era Hill University, Haldwani 263139, Uttarakhand, India
2. Department of Mathematics, Graphic Era Deemed to be University, Dehradun 248002, Uttarakhand, India
3. Department of Mathematics, Graphic Era Hill University, Bhimtal 263136, Uttarakhand, India
4. Faculty of Military Science, Stellenbosch University, Private Bag X2, Saldanha 7395, South Africa