Παραπομπή σε μορφή APA (7η εκδ.)

Radke, D. (1975). Contribution of the international tourism to the economic and social development of Sri Lanka. German Development Institute.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Radke, Detlef. Contribution of the International Tourism to the Economic and Social Development of Sri Lanka. Berlin: German Development Institute, 1975.

Παραπομπή σε μορφή MLA (9th εκδ.)

Radke, Detlef. Contribution of the International Tourism to the Economic and Social Development of Sri Lanka. German Development Institute, 1975.