APA (7th ed.) Citation

Nicolay, H. (1949). Lincoln's secretary: A biography of John G. Nicolay ([1st ed.].). Longmans, Green.

Chicago Style (17th ed.) Citation

Nicolay, Helen. Lincoln's Secretary: A Biography of John G. Nicolay. [1st ed.]. New York: Longmans, Green, 1949.

MLA (9th ed.) Citation

Nicolay, Helen. Lincoln's Secretary: A Biography of John G. Nicolay. [1st ed.]. Longmans, Green, 1949.