What primary/secondary sources can be used when writing a dissertation on Eisenhower and his engagement with the Civil Rights Movement?

Jul 2019
President Eisenhower is not famously known for his engagement with the Civil Rights Movement. However, upon inspection, he surprisingly contributed a significant amount to the advancement of black civil rights during his presidency. This is why I want to write my university dissertation on how far Ike engaged with the Civil Rights Movement but would like to see some suggestions on primary/secondary source material that I could access.