A citation, or reference, is the quoting, paraphrasing, or summarizing of someone else's work, used as a basis for your own ideas and research. A citation also refers to the information about a source, such as title, author, date, etc., which gives credit to the original author and shows readers where to find the original work. There are two parts to a citation: the in-text citation, which goes next to the quoted material, and the reference list citation, found at the end of a paper or report. This list is also called a bibliography.
Citations should follow a standardized format from a style guide such as APA (American Psychological Association) or MLA (Modern Language Association). Article databases have generic citations that you can put into other styles; you can also find all the necessary information from the source itself.
You need to cite anything that is not common knowledge, including when you don't use a word-for-word quote but still describe the main ideas or heart of a passage (called paraphrasing). But citing sources is more than just avoiding plagiarism. Citations give credibility to your work by showing that you've consulted other expert research, and references strengthen your work by putting it into meaningful context. You can cite other sources to establish general background information. More importantly, you can use them...
The new (6th) edition of APA asks for the DOI (Digital Object Identifier), if available, for citations for electronic journal articles. Note that a DOI does not always exist for an online article. If the article has one, it can sometimes be found in the database entry (but not always) or is often included with the Journal Name at either the top or bottom of the first page of the article itself.
Alternatively, if you have the citation information, you can look up the DOI number in CrossRef:
1. Go to CrossRef's Free DOI Lookup
2. Copy and paste your citation information and CrossRef will supply the DOI number, if available.