1941 A. Bester Probable Man Astounding S-F (July) № 88/1: In 2941 when you started your journey through Time, you were a reality. In 1941 you were a reality. But now, back in 2941, you're an alternative reality existing in the wrong alternate.
1990 Thrust (Winter) № 7/3: Bishop [...] dares to introduce sick unicorns from an alternative reality into our contemporary world of AIDS.
1994 P. Anderson Stars Are Also Fire № 97: The end of separatist Luna was in sight, however long a delaying campaign Niolente and her cohorts might wage. Yet, in some hypothetical quantum-mechanical alternative reality —