Παραπομπή σε μορφή APA (7η εκδ.)

Nijkamp, P., & Perrels, A. (1994). Sustainable cities in Europe: A comparative analysis of urban energy-environmental policies. Earthscan.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Nijkamp, Peter, και Adriaan Perrels. Sustainable Cities in Europe: A Comparative Analysis of Urban Energy-environmental Policies. London: Earthscan, 1994.

Παραπομπή σε μορφή MLA (9th εκδ.)

Nijkamp, Peter, και Adriaan Perrels. Sustainable Cities in Europe: A Comparative Analysis of Urban Energy-environmental Policies. Earthscan, 1994.