National Council for Preservation Education (U.S.). Preservation education & research. National Council for Preservation Education.
Παραπομπή σε μορφή Chicago (17η εκδ.)National Council for Preservation Education (U.S.). Preservation Education & Research. College Station, TX: National Council for Preservation Education.
Παραπομπή σε μορφή MLA (9th εκδ.)National Council for Preservation Education (U.S.). Preservation Education & Research. National Council for Preservation Education.
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