4-koma Koushiki Anthology: Toaru Kagaku no Railgun x Toaru Majutsu no Index

The 4-koma Koushiki Anthology: Toaru Kagaku no Railgun x Toaru Majutsu no Index (4コマ公式アンソロジー とある科学の×とある魔術の) is an official anthology comic series based on both Toaru Kagaku no Railgun and Toaru Majutsu no Index. Three volumes were released under the Dengeki Comics EX label, two in 2012 and one in 2013. All three have 4-koma stories created by various mangaka and artists including Kamachi Kazuma, Haimura Kiyotaka, and Fuyukawa Motoi.

Background
The first volume was released on March 27, 2012 and has stories illustrated by Inue Shinsuke (artist of the first Heavy Object manga), Kino, Sato, and Namori among others. The second volume was released on October 27, 2012 and has stories illustrated by Umino Tomo among others. The third volume was released on March 27, 2013 and has stories illustrated by Inue Shinsuke among others.