These are books I own and recommend.
Some may be out of print, but used copies may be available.
Check link. Start & Run a Greeting Cards Business
Book covers starting a card business in the UK.
Good basic info, but financial/measurement info is in different monetary units.
Creative Illustration Workshop
Exercises for integrating illustration with other mixed-media techniques, and scan and layer your illustrations using a computer.
Hand-Printing Techniques for low budgets. Interesting ways to put imagery on products. Perhaps a good technique for putting our designs on model items to show what they would look like on real products.
Printmaking techniques for fine art and how to transfer images to a variety of surfaces. It includes decals and skins.
Cutting-edge developments in international printmaking. Since printmaking is fundamental in most surface design concepts, this book's goal is a modern approach on a traditional printmaking.