McCullough, David (1992). Truman. New York: Simon and Schuster. pp. 347, 729. ISBN0-671-86920-5. Harry Truman is a notable example, as he bent and kissed the Bible upon taking the oath for the first time, on April 12, 1945, as well as at his second inauguration.
Peter Selby (1900). Anecdotal Lincoln. Thompson & Thomas. Retrieved 2010-08-07.
Foster, James Mitchell (1894) [1894]. Christ the King. Boston: James H. Earle. p. 277. In fact, Milligan did write to Lincoln, but his request was not that Lincoln add "so help me God" to the Oath, but rather that the name of Jesus Christ be added to the U.S. Constitution. [1]
archives.gov
Arbelbide, C. L. (Winter 2000). "Abrupt Transition". Prologue. Vol. 32, no. 4. Washington, D.C.: National Archives. Retrieved August 1, 2019.
Foster, James Mitchell (1894) [1894]. Christ the King. Boston: James H. Earle. p. 277. In fact, Milligan did write to Lincoln, but his request was not that Lincoln add "so help me God" to the Oath, but rather that the name of Jesus Christ be added to the U.S. Constitution. [1]