Nickels, W. G., McHugh, J. M., & McHugh, S. M. (2010). Understanding business (9th edition.). McGraw-Hill Irwin.

Nickels, William G., James M. McHugh, and Susan M. McHugh. Understanding Business. 9th edition. New York, NY: McGraw-Hill Irwin, 2010.

Nickels, William G., et al. Understanding Business. 9th edition. McGraw-Hill Irwin, 2010.