Tài liệu tham khảo WikiPedia: Frei_Otto http://cantic.bnc.cat/registres/CUCId/a10133288 http://www.designboom.com/history/ban_expo.html http://www.freiotto.com http://www.nytimes.com/2015/03/11/arts/design/frei... http://www.pritzkerprize.com/laureates/2015 http://www.dieterwunderlich.de/Frei_Otto.htm http://www.sl-rasch.de/ http://catalogo.bne.es/uhtbin/authoritybrowse.cgi?... http://uli.nli.org.il/F/?func=direct&doc_number=00... http://www.aspekt1.net/ms/fo_ref/einleit.html
