Παραπομπή σε μορφή APA (7η εκδ.)

Sperling, J. (1999). Two tiers or two speeds?: The European security order and the enlargement of the European Union and NATO. Manchester Univessity Press.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Sperling, James. Two Tiers or Two Speeds?: The European Security Order and the Enlargement of the European Union and NATO. Manchester: Manchester Univessity Press, 1999.

Παραπομπή σε μορφή MLA (9th εκδ.)

Sperling, James. Two Tiers or Two Speeds?: The European Security Order and the Enlargement of the European Union and NATO. Manchester Univessity Press, 1999.