A great book I found that really introduced the concept of 4ths was a book called

"Monster Chops" by Jack Grassel


It offers alot of cool ideas using 4ths. Each page offers different exercises in each position without giving them a musical context. The goal of this book is to highly excel our technique using 4ths and also totally destroy the idea of reading in "positions" because you are able to do such huge stretches and jumps with the left hand, you don't really need positions.