One set of rules for citing sources is called "APA," after a set of rules laid out in the Publication Manual of the American Psychological Association (APA). APA-style citations are what you will commonly use as a a college student.
The image below shows what a very, very short APA-style paper might look like:
This kind of writing has two features you don't see everyday: in-text citations and a reference list. Both of these are required by the APA style.
An in-text citation is simply a way of showing that an idea, fact, or quotation came from another author. An in-text citation consists of the other author's name and the year they published the work being used. It can go at the end of the sentence or the middle of a sentence.
There's a few ways to do in-text citations. The simplest is to put both the author's name and the year of publication in parentheses at the end of a sentence that draws on their work:
If you had already mentioned the author's name in the sentence, you wouldn't need to to put the name in the parentheses:
And if your sentence already includes the name of the author and the year the work was published, no parenthetical citation is necessary:
One last thing to consider: if you're citing information that can be found on a specific page or set of pages, do include the page numbers. That will make it easier for your readers to track down your source. So, for instance, you might also cite something like so:
So that's the basics of in-text citations. There are more complicated cases: multiple authors, no authors, etc. Fortunately, these can be quickly figured out by consulting an APA style guide (see the bottom box of this page).
An in-text citation does not have much information. If we wanted to find the Connor source cited in the first bullet point above, we would have a hard time. We don't know if it is a book or an article. We don't even know its title.
Fortunately, the in-text citation is just a pointer that tells us where to look in the reference list for the full details of a work. Every APA-style paper needs a reference list.
A reference list is a list of all the sources used in a paper. For each in-text citation, there needs to be an entry in the reference list. Each entry in the reference list provides enough detail on a source to go out in find it. So, even though the in-text citation for the Connor source doesn't have much detail, it's enough to point your reader to the reference list, where they would find this:
That's enough information to find the article in a library.
Putting together your reference list requires remembering more rules than doing in-text citations does. As such, when assembling a reference list you should consult an APA guide (see below).
There are many ways to learn the ins-and-outs of APA style. Here are some.