 Unlike the 1991 Marvel crossover storyline "The Infinity Gauntlet", where Marvel only published tie-ins in titles that needed a boost in sales, the vast majority of DC's comics featured events that directly tied to the crossover.The following comic book issues were labeled as part of the crossover; their covers contained a banner that read "Special "Crisis" Cross-Over", along with the logo for DC's fiftieth anniversary.The conflicting stories of the DCU are explained as a Multiverse, containing many parallel universes and alternate versions of the characters, with the primary DC continuity referred to as Earth-One.