I'm looking here for references for a second lecture. When you start learning mathematics, there are books that you have to read because there is every basic thing that you should know about this topic, because the course is extremely clear, the examples are well chosen to apply the definitions, and there are basic problems to evaluate how well you understand the theorems.
Here I'm looking for different kinds of books : The books that you read when you know the theory, that choose a different point of view (not recommended for a beginner). The exercises and problems are here to test the limit of the theory, to expand the theory, or to develop counterexamples that you didn't want to see at first. For example, some people may say that the 4-volume course of Analysis by R. Godement is one of those books.
Do you have some other examples of these kinds of books? (about what a math undergraduate should know : Algebra, Linear Algebra, Integration, Real Analysis, Probability Theory, Arithmetic, Complex Analysis, Geometry...)
Until now, I only have suggestions for Algebra, Differential Geometry and Riemann Surfaces (this domain may be to specific, I'm not sure that all undergrads are aware of Riemann Surfaces).