Sewn and notch bound books can be bound as either hardbacks or paperbacks. Perma-Bound rebinds books for libraries and schools, and turns paperbacks into hardbacks. Business practices by publishers and booksellers also differentiate mass-market paperbacks from hardbacks. The series has been collected into a series of trade paperbacks and deluxe hardbacks. These books range in format from large hardbacks to slim paperback guides. Horse Comics is reprinting EC comics in high quality full color hardbacks. These again were slightly larger than the originals, but were hardbacks. The two Arthur Barker hardbacks were credited to Ken Blake. Similar hardbacks were produced showcasing work by favourite "Archie" creators.