Magazines: Articles in magazines are usually short in length and are written in a popular style. An example of a magazine that has articles on The United Nations is UN Chronicle.
Journals: Articles in journals are usually lengthy and are written by scholars and experts in the field.
They often have bibliographies and extensive footnotes (which can provide leads to other sources).
Examples of journals that have articles on The United Nations are Foreign Affairs and Journal of Peace Research.
HINT: When conducting your search, be sure to use "United Nations" rather than "UN."