- Music Theory Fundamentals: http://academic.udayton.edu/tobyrush/theorypages/
- 7 Important Chords: http://www.mypianoriffs.com/279/7-important-chords-every-musician-should-know/
- The Cipher: http://www.thecipher.com/bass-guitar-cipher.html
- The diatonic signature
. Triads in all of the major keys: http://www.practical-chords-and-harmony.com/diatonic-triads.html
. Seventh Chords in all of the major keys: http://www.practical-chords-and-harmony.com/diatonic-seventh-chords.html
- Major scale harmonizing: http://www.musicfield.co.kr/Dataroom/?mode=ViewBoard&type=&code=DATAROOM&bbid=11&cate=13&page=1&nums=7665&sfl=&stx=
- 화음: http://www.musicnlife.com/books/b04mint/p036_041.htm
