Get Started Digital Painting with Krita
Get Started Digital Painting with Krita, available at $54.99
Opentoonz: A to Z
Opentoonz: A to Z, available at $49.99
Getting Started in Inkscape
Getting Started in Inkscape, available at $69.99
Beginners Digital Illustration with Krita
Beginners Digital Illustration with Krita, available at Free