Sometimes, researchers only seek general information, and are not concerned with learning everything about a subject. For example, one might want to know what the UN's role has been in Rwanda lately. In other cases, researchers may be new to UN research and want to start their research gradually. In either case, starting out with complex indexes can be counter-productive. The search strategies, the lists of documents, and the symbol system can be overwhelming.
For general research, using one of the following text-based sources is a more user-friendly approach. They often provide more than enough information to satisfy requests. Alternatively, they are great starting points. Note that in most cases humans, not computers, compile these sources. The benefit of this is that the sources are user-friendly. The disadvantage is that publication is quite slow. These strategies may not be appropriate for current research.