You may want to look at how citations are done in an actual outline. Click here to do so. Normally a citation is included at the end of a sentence to indicate where the information in that sentence came from. If it is included at the end of a sentence, for example, that is your main point, we assume that everything that follows to support that main point comes from that source. Anytime you change sources, you must have a new citation.
Oral citations apply specifically to a speech.
They serve the same purpose as the written citations. They tell the audience where your information came from. According to Dr. John Smith, Professor of Psychology at Harvard University . . . . Sometimes telling where the article was published is the best way to start the citation. This works particularly well for scholarly journals, such as the Journal of the American Medical Association.