1: Wikipedia

2: The White House.gov- Bio of Coolidge

3: Millercenter.org- Bio of Coolidge

4: Calvin-Coolidge.org- Memorial Foundation

5: History.com- History Channel

6: Brainyquote.com- Calvin Coolidge quotes

7: Forbeslibrary.com

8: Britannica.com

9: Ipl.org- Internet Public Library

10: pbs.org