Elkington, J., & Hartigan, P. (2008). The power of unreasonable people: How social entrepreneurs create markets that change the world. Harvard Business School Press.

Elkington, John, and Pamela Hartigan. The Power of Unreasonable People: How Social Entrepreneurs Create Markets That Change the World. Boston, Mass.: Harvard Business School Press, 2008.

Elkington, John, and Pamela Hartigan. The Power of Unreasonable People: How Social Entrepreneurs Create Markets That Change the World. Harvard Business School Press, 2008.