Craig Glenday: Guinness World Records 2009. Nowy Jork, Stany Zjednoczone: Random House, 2009, s. 241. ISBN 978-0-553-59256-6. [dostęp 2021-10-13]. Cytat: Most popular MMORPG game(sic) In terms of the number of online subscribers, World of Warcraft is the most popular Massively Multiplayer Online Role-Playing Game (MMORPG), with 10 million subscribers as of January 2008. (ang.).
Becky Williams: Video: Backstage at BlizzCon 2009. The Telegraph, 2009-08-24. [dostęp 2021-10-14]. (ang.). („Set in the fantasy world of Azeroth it currently holds the Guinness World Record for the most popular MMORPG, which probably accounts for why Blizzard is the most bankable games publisher in the world.”).