ECONOMIST INTELLIGENCE UNIT. (1999). BEST PRACTICES ENVIRONMENT. UNIVERSITY PRESS.
Chicago Style aipamenaECONOMIST INTELLIGENCE UNIT. BEST PRACTICES ENVIRONMENT. NEW DELHI: UNIVERSITY PRESS, 1999.
MLA aipamenaECONOMIST INTELLIGENCE UNIT. BEST PRACTICES ENVIRONMENT. UNIVERSITY PRESS, 1999.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.