As for the previous one, the story is split into 4 parts -- 1 part per protagonist as the story progresses -- so each cover will feature its main protagonist, and I've got the references in place in order,
(Medee)
https://i.imgur.com/Z8amVTi.jpg
(Bazett)
https://i.imgur.com/Ahww2WW.jpg?1
(Misaya)
https://i.imgur.com/6mYpc1u.jpg?1
(Cary)
https://i.imgur.com/XL0h7vM.jpg