- Inequalities: an olympid approach --- Nice book, has an axiomatic/algebraic bent.
- Mathematical circles: Russian experience
- The art and craft of problem solving
- Basics of Olympiad Inequalities: Samin Riasat --- quickly covers the big 12.
- Evan chen: A Brief Introduction to Olympiad Inequalities
- Pham Kim Hung: Secrets in Inequalities
- Edwin Beckenback: Introduction to Inequalities
- Nicholas D. Kazarinoff : Geometric inequalities
- Introduction to Functional Equations: Theory and problem-solving strategies for mathematical competitions and beyond
- Combinatorics: Introduction to counting and probability
- Combinatorics: Intermediate counting and probability
- Algebra: 101 Problems in Algebra by Titu Andreescu
- Number Theory Structures, Examples and Problems
- Combinatorics: 102 Combinatorial problems
- Combinatorics: Pablo Soberon’s Problem Solving Methods in Combinatorics
- Geometry: Yufi Zhao: handouts
- Geometry: Trig bashing / Barycentric bashing (evan cheng)
- Problem-solving Strategies In Mathematics: From Common Approaches To Exemplary Strategies
- Problems from the Book
- Straight From the Book
- AoPS list of past problems
- AoPS list of books
- Mathematical problem solving: MIT course