These book cover and poster mockups are part of a student project. These particular ones being produced by Sebit Min who, unfortunately, doesn’t appear to have an online presence (not that I could find, at least). A quick search for the name did throw up one other peice of work, which you’ll find around two thirds of the way down this page. One to watch our for.
You’ll find details of the project brief and work by other students in this post on John Gall’s Spine Out blog.
