Gardner, L. C., & Oneill, W. L. (1974). Looking backward: A reintroduction to American history. McGraw-Hill.

Gardner, Lloyd C., and William L. Oneill. Looking Backward: A Reintroduction to American History. New York: McGraw-Hill, 1974.

Gardner, Lloyd C., and William L. Oneill. Looking Backward: A Reintroduction to American History. McGraw-Hill, 1974.