Designing virtual worlds, c2004: t.p. (Richard A. Bartle) p. xiv (Ph.d.; lives outside Colchester, England)

Author's Web site, Sept. 30, 2005 (Richard Allan Bartle; b. Ripon, Eng., Jan. 10, 1960; Ph. D., Essex U. in Artificial intelligence; has designed computer games and worked as a consultant; visting professor at Essex U.)

Biblioteca del congreso (Estados Unidos), 22 mayo 2019: catálogo electrónico https://bit.ly/2Bk7Wc5