Troy Nelson
Guitar Aerobics: A 52-Week, One-lick-per-day Workout Program for Developing, Improving and Maintaining Guitar Technique
Fretboard Freedom: A 52-Week, One-Lick-Per-Day Method for Visualizing and Navigating the Neck of the Guitar
How to Play Guitar in 14 Days: Daily Guitar Lessons for Beginners (Play Music in 14 Days)