Mirrored with permission from bahaimp3.narod.ru. Date not given, but Correa refers to "these, the last of this series of talks," which would put it around 2008.
Documents posted between 2003-2012 had various slightly different URLs and sometimes can be found in archive.org with addresses like bahai-library.com/file.php5?file=correa_working_betterment_society.