Symmetrical and Other Scales for Seven String Guitar (Basic Scale Guides for Seven String Guitar Book 4) - Kindle edition by Silver, Rob . Arts & Photography Kindle eBooks @ Amazon.com.
Chad Johnson “ 7-string Guitar Chord Book” - 2002 | Reverb
1st Chord Book For The 7-string Guitar by Sims Jerry for Guitar
7-String Guitar: Book & CD (Paperback) - Walmart.com