Whittier, J. G., & Warren, R. P. (1971). John Greenleaf Whittier's poetry: An appraisal and a selection. University of Minnesota Press.

Whittier, John Greenleaf, and Robert Penn Warren. John Greenleaf Whittier's Poetry: An Appraisal and a Selection. Minneapolis: University of Minnesota Press, 1971.

Whittier, John Greenleaf, and Robert Penn Warren. John Greenleaf Whittier's Poetry: An Appraisal and a Selection. University of Minnesota Press, 1971.