To identify books and articles to request via ILL, you can search WorldCat.org, which allows you to look through the catalogs of libraries all over the world.
Search the collections of over 10,000 libraries worldwide and request them. Click on the title of the item you want, then click View Access Options and Request through Interlibrary Loan. First-time users of Interlibrary Loan will need to create a free account.