HI,

Let me be clear for CSIR NET Mathematics, you need to have decent mathematical understanding. You need to have clear undertanding of concepts about the topic rather than mere calculations.

• Integral Equations And Boundary Value Problems - By Dr. M. D. Raisinghania
• Introduction to Real analysis, Robert Bartle, SR Sherbert
• How to Become a Human Calculator -Aditi Singhal
• Linear Algebra, SH friedberg,AJ insel,LE,spence
• Advanced Differential Equations - M.D.Raisinghania
• Ordinary and Partial Differential Equations - M D Raisinghania
• Foundations of complex analysis, S. Ponnusammy

Hope this helps!