Examples of Hand Illustrated Book Covers: http://www.chrissheban.com/chris/home.html
Bar Code examples: http://100scopenotes.com/2015/03/18/gallery-the-art-of-the-picture-book-barcode/
http://stevesimpson.com/17721/1202053/portfolio/illustrated-barcodes
Examples of Illustrated Book Covers: http://bookcoverarchive.com/