"Rockefeller Center". National Historic Landmark summary listing. National Park Service. September 18, 2007. Archived from the original on 11 اكتبر 2012. Retrieved 23 May 2013. {{cite web}}: Check date values in: |archive-date= (help)
web.archive.org
"Rockefeller Center". National Historic Landmark summary listing. National Park Service. September 18, 2007. Archived from the original on 11 اكتبر 2012. Retrieved 23 May 2013. {{cite web}}: Check date values in: |archive-date= (help)