50m Subscribers - Shopping site sensation”. January 21, 2011閲覧。 ^ a b BARIWEISS (DECEMBER 18, 2010). “Groupon's $6 Billion Gambler”. Wall Street Journal
archive.org/web/20230122044459/https://www.businessinsider.com/elon-musk-bari-weiss-the-twitter-files-blacklisted-accounts-2022-12 December 9, 2022閲覧。 ^