What are good books to learn graph theory? What are some of the best books on graph theory, particularly directed towards an upper division undergraduate student who has taken most the standard undergraduate courses? I'm learning graph theory as part of a combinatorics course, and would like to look deeper into it on my own. Thank you.

Here is Vadim Lozin's graph theory course. (Available for free from university of Warwick website )
It starts from scratch and most of theorems are prooved. I think it's pretty clear with many content.
It's not a book, but i hope it can help you.
