User blog comment:FairyRaven/Fairy Tail Chapter 425: Sabertooth X792, Review and Commentary/@comment-24553184-20150323232715/@comment-1359322-20150324003847

So when you reference your assignment, do you say you ripoff your entire assignment from other authors? No you don't, cause you edit it to fit into your topic, it's the same logic as that, Mashima reference it from other mangas and change it to fit into his own story.