Stableford, Brian. "Alternate Worlds"
Comments: Encyclopedia entry citing various titles.
Published: In The Encyclopedia of Science Fiction, 2nd ed. (eds. John Clute and Peter Nicholls), Orbit 1993 (1857231244), 1999 (1857238974w88 android); St. Martin's 1993 (0312096186BUY); St. Martin's/Griffin 1995 (031213486XBUY); SFBC 1996.
— Revision of "Alternate Worlds", in The Encyclopedia of Science Fiction: An Illustrated A to Z (ed. Peter Nicholls), Granada 1979 (0246110201), v.t. The Science Fiction Encyclopedia, Doubleday/Dolphin 1979 (0385147430).

Stableford, Brian. "An Introduction to Alternate Worlds"
Comments: A much expanded version of the "Alternate Worlds" essay in ESF2, in conjunction with the premier (and only) issue of Alternate Worlds magazine.
Published: In Alternate Worlds #1 (January 1994).