I have published 3 Apps based on/inspired by RW’s iOS Apprentice book:
8Bullseye Section 1: Getting Started
8Done Section 2: Checklists
8Places Section 3: My Locations
Each app has a Credits page, with prominent mention of Matthijs Hollemans and the Ray Wenderlich team.
Thank you RW sincerely for enriching my life, and those of my users/players of my apps/games, with your excellent world-class books, articles & videos.
Here are the links: