Stephenson, S. (1999). Approaches to liberalizing services. World Bank.
Chicago Style aipamenaStephenson, Sherry. Approaches to Liberalizing Services. Washington, DC: World Bank, 1999.
MLA aipamenaStephenson, Sherry. Approaches to Liberalizing Services. World Bank, 1999.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.