When you become close enough friends with Diasuke, he will invite you on a Sunday outing to hang out. On one of these outings, you will be given a book "Witch Detective" Which you can read at home on your couch. When reading, a reference to the book series...
more
If you look closely at Yosuke's bike, you'll notice that the name "Atlus" is write in it. This is a reference to the company that make the game, Atlus
