These would include (but need not be limited to) books, magazine articles, journal articles (really serious magazines), reference books, and the internet.
Avoid using too many newspaper articles and magazines wherever you can.
Consult the online catalog first to see what's available. Sign out those library books and copy those journal articles early on in the process, or you may find some prof has absconded with the only copy of your best source, and good luck getting it back before Christmas.
Or some bozo has neatly cut out every article on your hot topic (which, by an odd coincidence, was the hot topic for thirty other students just last semester). If you have a specific title or author, it's pretty easy to type it in an online catalog or database, and see what happens.
Collections of state documents can also be an invaluable source for certain topics, such as local environmental problems. Modern university libraries have most of their collections online.
Every university library has its own database for books and journals.If you get zip, try thinking of alternate terms, synonyms, slang etc. Usually you get way too much, because in our haste to get everything online, we've indexed everything to death.So a search on alligators turns up everything from wildlife to recipes.Every system has a different "wild card" character (usually a ? Not Every Library Has Every Book Or Journal, or every issue of every journal.Find out what sources are NOT available locally, but potentially valuable to your paper.No more than one third of your sources should come from magazines or the internet, unless they refer to actual data.If your entire argument is built upon a stack of Newsweeks, it will tremble in the slightest breeze. Try to use several different types of sources in your research. By the time you finish your research and writing, you might well be genuinely sick to death of your topic (ask any graduate student who's just completed a dissertation! But if you're bored when you start, you've already defeated yourself, and turned a potentially interesting assignment into yet more drudgery. If cloning is too broad for a five page paper, what about cloning Elvis? Make sure that you find this topic genuinely interesting, or find some aspect of it that is especially cool. If your topic is way too broad, try homing in on some part of that topic, and exploring that area in more depth.Use it on your first draft to get your bearings, or on your final draft to check the way you’ve organized your paragraphs. Many papers may have more than that, but if yours has less, you probably skimped in the endless hours in the library department.Even better, papers should draw on a variety of sources, which usually boils down to books, essays, journal articles and/or magazines.