Παραπομπή σε μορφή APA (7η εκδ.)

Langfield, M. (2007). As sete chaves. Civilização.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Langfield, Martin. As Sete Chaves. Civilização, 2007.

Παραπομπή σε μορφή MLA (8th εκδ.)

Langfield, Martin. As Sete Chaves. Civilização, 2007.