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