Berman Saul J. (2011). Not For Free: Revenue Strategies for a new world. Harvard Business Review Press.
Chicago Style aipamenaBerman Saul J. Not For Free: Revenue Strategies for a New World. Boston: Harvard Business Review Press, 2011.
MLA aipamenaBerman Saul J. Not For Free: Revenue Strategies for a New World. Harvard Business Review Press, 2011.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.