The J29 Project, 2012. - 165 с.
This problem set is my main source for writing a book. It is nothing but a set of problems posted by active users of AoPS/MathLinks, and it will be a really good source for preparing for mathematical olympiads.
Problems
Amir Hossein.
Andrew.
Goutham.
Orlando.
Valentin.
Darij.
Vesselin.
Gabriel.
April.
Arne.
Kunihiko.
Solutions