Schultz, M., Doerr, J. E., & Frederiksen, L. W. (2009). Professional services marketing: How the best firms build premier brands, thriving lead generation engines, and cultures of business development success (2nd ed.). John Wiley & Sons, INC.

Schultz, Mike, John E. Doerr, and Lee W. Frederiksen. Professional Services Marketing: How the Best Firms Build Premier Brands, Thriving Lead Generation Engines, and Cultures of Business Development Success. 2nd ed. New Jersey: John Wiley & Sons, INC, 2009.

Schultz, Mike, et al. Professional Services Marketing: How the Best Firms Build Premier Brands, Thriving Lead Generation Engines, and Cultures of Business Development Success. 2nd ed. John Wiley & Sons, INC, 2009.