4-Chord Songs for the Absolute Beginner: Guitar Book & Online Audio
Pop Song Secrets - Chord Progressions That Sell
What are the four chords in the four-chord song? - Classic FM
4 Chords, 21 Pop Songs on Acoustic Guitar! | I sing 21 pop songs on top of the same 4 chords! Learn how to produce your own acoustic songs :-) http://bit.ly/acousticlearn