When preparing your presentation, remember that all sources used must be cited in both the Works Cited page and in-text. For a speech you will need to verbally give credit to your sources. Verbally citing a source can be as simple as stating, "Dr. Bob, a Professor at Clemson University, stated in a 2019 Forbes article, ..." Other examples could be, "The World Health Organization published the following Zika virus statistics on April 12, 2016...," or "According to Neal's book we learned..."
By verbally citing your sources you are lending credibility to your topic and making your position stronger. Be sure to vary the language in which you verbally cite sources to keep your presentation more interesting (don't say "According to..." every time).