Actual publisher is Flame Tree Publishing.
"See it hear it sound links."
Each page has a QR code that you can use with a smartphone with a QR app to access a dedicated website allowing you to hear the chord illustrated on that page.
Guitar chords made easy by Jake Jackson. ISBN 9780857757982. Published by Flame Tree Music/Flame Tree Publishing in 2013. Publication and catalogue information, links to buy online and reader comments.