It is never okay to quote someone without proper attribution. Standard citation styles are required to ensure strict adherence to this principle.
APA Citation - Guide
MLA Citation - Guide
Chicago Style - Guide
A "Works Cited" page should include not just quoted sources but also all sources referred to, summarized, or paraphrased.
Unpublished or informally published works generally do not have the established authority that a peer-reviewed published work might, such as works in progress, works stored in a university database, or works on an author's website. However, any referenced material (published or unpublished - directly referenced, summarized, or paraphrased) MUST be properly cited, regardless of publication status.
Using the formatting function in a database record to generate a citation (MLA, APA, Chicago Style, etc.) is a great convenience. But you cannot blindly copy and paste and then hand it in without checking to make sure it is correct. There will sometimes be mistakes in the citations. Therefore, you MUST double check them according to the style guide.