links

research works by Helmuth Lemme

https://www.buildyourguitar.com/resources/lemme

https://www.planetz.com/wp-content/uploads/2014/10/Pickup_Measuring_Technique.pdf

https://www.elektor.com/electric-guitar-2nd-edition-e-book

https://www.inside-electric-guitars.com

https://www.gitarrenelektronik.de

https://www.facebook.com/gitarrenelektronik/posts

further more

https://www.bassrefiner.com