Boyer, P. S., Clark, C. E., Kett, J. F., Salisbury, N., Sitkoff, H., & Woloch, N. (1993). The enduring vision: A history of the american people (2. edition.). Lexington: D. C. Heath and Company.

Boyer, Paul S., Clifford E. Clark, Joseph F. Kett, Neal Salisbury, Harvard Sitkoff, and Nancy Woloch. The Enduring Vision: A History of the American People. 2. edition. Lexington: D. C. Heath and Company, 1993.

Boyer, Paul S., et al. The Enduring Vision: A History of the American People. 2. edition. Lexington: D. C. Heath and Company, 1993.