* [https://web.archive.org/web/20050508113233/http://www.belgium.be/eportal/application?origin=searchResults.jsp&event=bea.portal.framework.internal.refresh&pageid=contentPage&docId=5852 比利时政府网站对奥塔的介绍]

* [http://www.cupola.com/html/bldgstru/artnouv/artnouv1.htm cupola.com]