Karlson David. (2004). Marketing Your Consulting or Professional Services. Viva Books.
Chicago Style aipamenaKarlson David. Marketing Your Consulting or Professional Services. New Delhi: Viva Books, 2004.
MLA aipamenaKarlson David. Marketing Your Consulting or Professional Services. Viva Books, 2004.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.