Useful References

I will put references (sometimes with hyperlinks) which are useful in my humble opinion.

T.A.Springer Linear Algebraic Groups: A famous textbook for the theory of linear algebraic groups with preliminaries. It is also useful as a reference for structure theorem of reductive groups (Chapter 9). I remember that my advisor, Yoichi, recommended this book to me when I asked how to start learning representation theory of reductive groups.