Não informado. Student world. World's Student Christian Federation.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Student World. Geneva, Suíça: World's Student Christian Federation.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Student World. World's Student Christian Federation.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.