Olympiad Problems from all over the World. 9th Grade Content. Volumul 5/D.M. Batinetu-Giurgiu, Marin Chirciu, Daniel Sitaru, Neculai Stanciu, Octavian Stroe

"The book contains 400 problems in algebra, number theory, combinatorics, and geometry, from all over the world. It is an excellent text for preparing mathematics competitions of all levels. That is why I stongly recommend this book for mathematics teachers and gifted students." - Radu Gologan, President of the Romanian Mathematical Society