Bowen, H. R., & Douglas, G. K. (1971). Efficiency in liberal education: A study of comparative instructional costs for different ways of organizing teaching-learning in a liberal arts college. McGraw-Hill.

Bowen, Howard Rothmann, and Gordon K. Douglas. Efficiency in Liberal Education: A Study of Comparative Instructional Costs for Different Ways of Organizing Teaching-learning in a Liberal Arts College. New York: McGraw-Hill, 1971.

Bowen, Howard Rothmann, and Gordon K. Douglas. Efficiency in Liberal Education: A Study of Comparative Instructional Costs for Different Ways of Organizing Teaching-learning in a Liberal Arts College. McGraw-Hill, 1971.