File:Progressive Manga Vol 4 Cover.png

Summary
Current source: http://gs.dengeki.com/news/44573/ (http://gs.dengeki.com/ss/gs/uploads/2015/08/d89984939cb5f1d310542b7cf51831cd-718x1024.jpg)

Original source: http://dc.dengeki.com/newreleases/978-4-04-865304-6/