Clayton, G. E., & Gary E. Clayton. Economics: Principles and Practices, Reading Essentials and Note-Taking guide student workbook. New York: Glencoe/McGraw-Hill.

Clayton, Gary E., و Gary E. Clayton. Economics: Principles and Practices, Reading Essentials and Note-Taking Guide Student Workbook. New York: Glencoe/McGraw-Hill.

Clayton, Gary E., و Gary E. Clayton. Economics: Principles and Practices, Reading Essentials and Note-Taking Guide Student Workbook. New York: Glencoe/McGraw-Hill.