The amount number of information sources available to you is massive, so before you start your research think carefully about what type of information are you looking for in regards to your MUN topic.
Information is available through many sources - books, periodical articles, scholarly articles, websites, journal articles, encyclopedias, government documents - the list is endless.
Be careful of where the information has come from. Ask yourself which country disseminated the information? Who is the intended audience? Is the information accurate or biased?