PDFs are available in two languages: uhj_day_covenant_2003.pdf (English) and uhj_day_covenant_2003_persian.pdf (Persian).
Documents posted between 2003-2012 had slightly different URLs and can be found in archive.org with addresses like bahai-library.com/?file=uhj_day_covenant_2003.
Documents posted prior to October 2003 were at bahai-library.org [archive.org] and had completely different URLs.