Depending upon the subject you are writing for, identify your sources according to the proper citation style as instructed by your professor. Citations vary according to style, source type and format.

Citation Style - What is the required style for the course or discipline? (ACS, APA, MLA,Turabian, SBL)
Citation styles vary by discipline. Always consult the print library resources or the association's official web page(s) for exact guidelines.

Type of Source - What are you citing? (book, journal article, website, interview)

Format - How was it delivered? (print, Web, audio/visual)
Book and article citations for an online resource, such as library ebook or article databases, may require more documentation than for the hard copy (print) resources. For example, the citation for an online source may need to include some of following:
• database name
• service provider (i.e., EBSCO or ProQuest)
• URL or opens new windowDOI
• accessed date

As shown below, citations for books differ from article citations.