Developed by the American Psychological Association, APA format is favored by those in the sciences and social sciences. Typically, professional researchers in these fields must use APA in order to have their work published.
From Purdue OWL's APA Style Workshop:
Aside from simplifying the work of editors by having everyone use the same format for a given publication, using APA Style makes it easier for readers to understand a text by providing a familiar structure they can follow. Abiding by APA's standards as a writer will allow you to:
DOI stands for Digital Object Identifier. This is a unique number that identifies a particular article. You can usually find the DOI listed along with the other citation information, on the first page, and/or on the abstract page. Conversely, DOI numbers can be entered into crossref.org and the citation information will be provided.
Not all articles have a DOI number. If no DOI is provided you'll need to provide the URL of the journal's website. This is NOT the website to the database, so you can't necessarily copy and paste the URL you're using! An easy way to locate the journal URL is to search for the journal title in Google.
Online citation builders are helpful when you are in a rush and have a small number of sources to manage. Typically, citations are not saved and cannot be exported to a word processor using the free versions of these tools. You can copy and paste a formatted citation into your document. Use the links below to try some free tools.
Citation software like Zotero and Endnote are more time consuming to learn but extremely useful for saving and organizing larger, more complex collections of sources and their citations. For smaller projects, you may consider emailing articles you've found to yourself as a means of archiving them.
No citation manager is perfect - though they are a great way to start, you should always double check to make sure your citations are correct.
Not sure what citation management software to use? Check out PennState's Citation Tools Comparison Chart to see how Zotero, Mendeley, Endnote, and Endnote Basic compare!