The League of Nations (1919-1946) was the predecessor to the United Nations. University of Toronto has a large collection of League materials in microfilm as well as an extensive print collection of primary source documents from the League that can be searched through the library catalogue.
You can find many League of Nations publications through U of T Library's LibrarySearch. However, some research will require additional bibliographies to find the relevant material. Use the resources listed in the Finding Aids tab to locate items that are not indexed in the catalogue.