This is the Yamaha Corporation [Musical Instrument Guide] website. This article contains information about the Acoustic guitar [The Structure of the Acoustic Guitar:The rule of strings and pitch]
Acoustic Guitar Buying Guide for Beginners
How Often Should You Change Your Guitar Strings?
What's the difference between 6-string and 12-string guitars
DIY Adjusting String Action on Acoustic Guitar - Stoll Guitars
Back View of Tanglewood Steel String Guitar Opened Up to S…
Guitar - Wikipedia
How to Change Guitar Strings (Acoustic or Electric Guitars)
String Family - Mr. Q's Music, Strings
Guitar Accessories Guides Guitar Strings - What to buy?
Slotted Headstocks: Look Cool, Sound Great - Takamine
What are the parts of a guitar?