Παραπομπή σε μορφή APA (7η εκδ.)

Helmer. Al Capone and His American Boys. Indiana University Press.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Helmer. Al Capone and His American Boys. Indiana University Press.

Παραπομπή σε μορφή MLA (8th εκδ.)

Helmer. Al Capone and His American Boys. Indiana University Press.