- IMAR Tests: These are a series of tests organized biannually by the Mathematics Institute of the Romanian Academy (IMAR). All students are invited, particularly those who are interested in taking the IMO Team Selection Tests in the following year.
- 77 de Ture: This is a collection of 77 mathematics problems gathered from IMO team leaders from around the world. The Romanian IMO 2004 team used these problems as practice.
- MOSP: The US IMO team Math Olympiad Summer Program.
- JMBO: Junior Balkan Mathematics Olympiad.
- American Mathematical Monthly or AMM: This is probably the most important American mathematics periodical.
- Team Contest: These problems were given at a team contest organized in 2004 by several Romanian college students who were IMO veterans for their younger peers.
- Mathlinks Contest: This is the contest organized yearly (or biannually) by the Mathlinks forum.
- Romanian-Hungarian Training Camp: This is the yearly common IMO training of the Romanian and Hungarian teams. The camp lasts for one week and is organized alternatively by the two countries.
- William Lowell Putnam: This is the most important math competition organized in the USA for undergraduate students.

If you know some more sources, please share with us.

Cheers,

Nalin Pithwa