APA (7th ed.) Citation

Ingersoll, R. G. (1983). Some reasons why I am a freethinker: A lecture. American Atheist Press.

Chicago Style (17th ed.) Citation

Ingersoll, Robert Green. Some Reasons Why I Am a Freethinker: A Lecture. Austin, Tx: American Atheist Press, 1983.

MLA (8th ed.) Citation

Ingersoll, Robert Green. Some Reasons Why I Am a Freethinker: A Lecture. American Atheist Press, 1983.