MLA
Day, Reuben Alexander, Jr. Four Days in May, 1969, Materials Regarding the Student Demonstrations at Emory between May 25th and 28th, 1969 - Correspondence - ???A Personal Letter to Emory Freshmen from a Concerned Professor" [R. A. Day Jr.] Regarding Racial Issues at Emory and Asking Students to ???Keep Your Cool?ﾩ - September 1969. 1969. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 1, Folder 8. https://digital.library.emory.edu/purl/709w0vt551-cor.
APA, 6th edition
Day, R. A., Jr. (1969). Four days in May, 1969, Materials regarding the student demonstrations at Emory between May 25th and 28th, 1969 - Correspondence - ???A Personal Letter to Emory Freshmen from a Concerned Professor" [R. A. Day Jr.] regarding racial issues at Emory and asking students to ???keep your cool?ﾩ - September 1969 (Box 1, Folder 8) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/709w0vt551-cor.
Chicago
Day, Reuben Alexander, Jr. “Four Days in May, 1969, Materials Regarding the Student Demonstrations at Emory between May 25th and 28th, 1969 - Correspondence - ???A Personal Letter to Emory Freshmen from a Concerned Professor’ [R. A. Day Jr.] Regarding Racial Issues at Emory and Asking Students to ???Keep Your Cool?ﾩ - September 1969.” Letters (correspondence). Emory University Desegregation Collection, 1969. Box 1, Folder 8. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/709w0vt551-cor.