Aquila 89U Red Series Baritone Low-D Tuning Ukulele Strings
Amazon.com: Baritone Ukulele Chords In A Case: DGBE Standard Tuning 1,512 Chords In All Keys (Fretted Friends Chords In A Case): 9781912087761: Richards, Tobe A.: Books
Ukulele Tuning: The Ultimate Guide For How to Tune Your Ukulele | Ukulele Tricks
Baritone Ukulele Basics: Expand Your Sound | Ukulele Magazine