I was thinking of participating in the Next years IMO(international mathematics Olympiad) and i wanted some book references to help me get to the Olympiad level . The topics are : Algebra , Geometry , Combinatorics , and Number theory. I am currently a high school student with a very basic knowledge in number theory , some graphs and algorithms in combinatorics, and just high school algebra . So, if you will , bearing in mind my very basic level, refer some books ( preferably 1 -the best in your opinion- in each topic) Thanks.
Try this links. Books which specific in every level according to the level.