APA (7th ed.) Citation

O'Neill, E. (1972). Long day's journey into night (1st. published, 25th printing.). Yale University Press.

Chicago Style (17th ed.) Citation

O'Neill, Eugene. Long Day's Journey into Night. 1st. published, 25th printing. New Haven [etc.]: Yale University Press, 1972.

MLA (9th ed.) Citation

O'Neill, Eugene. Long Day's Journey into Night. 1st. published, 25th printing. Yale University Press, 1972.