Amazon.com: D'Addario EXP19 Coated Phosphor Bronze Acoustic Guitar Strings, Light, 12-56 – Offers a Warm, Bright and Well-Balanced Acoustic Tone and 4x Longer Life - With NY Steel for Strength and Pitch
Coated vs. Uncoated Guitar Strings: What are the differences? – Ernie Ball Blog
Tools for the Task: Coated Strings - Premier Guitar