Παραπομπή σε μορφή APA (7η εκδ.)
Van Opstal A. J. (1999). The Architecture of the Pan European Ecological Network: Discussion report on behalf of the Committee of Experts of the Pan European Ecological Network. IKC Natuurbeheer.(National Reference centre for Nature Management).
Παραπομπή σε μορφή Chicago (17η εκδ.)
Van Opstal A. J. The Architecture of the Pan European Ecological Network: Discussion Report on Behalf of the Committee of Experts of the Pan European Ecological Network. IKC Natuurbeheer.(National Reference centre for Nature Management), 1999.
Παραπομπή σε μορφή MLA (9th εκδ.)
Van Opstal A. J. The Architecture of the Pan European Ecological Network: Discussion Report on Behalf of the Committee of Experts of the Pan European Ecological Network. IKC Natuurbeheer.(National Reference centre for Nature Management), 1999.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.