From the introduction to Lisa DeLuca’s Presidential research resources: A guide to online information, College & Research Libraries News, v. 79, n. 2, p. 93, Feb. 2018:
This article highlights the breadth of freely available digital collections of presidential documents. These repositories are excellent resources for presidential, political science, history, and foreign relations research. From the resources listed in this article, librarians can choose multiple starting points for student and faculty research inquiries for primary and secondary sources that include handwritten documents by the founding fathers, interview transcriptions, digitized documents, and photographs, to name a few. This article does not contain public opinion, election, or media content sources, which are an important component of presidential research.
H/T to beSpacific. — Joe