- Comercio exterior del libro 2021
https://www.gremieditors.cat/wp-content/uploads/2023/01/comerc-exterior-21-fedecali.pdf

- Comercio exterior del libro 2020
https://fedecali.es/wp-content/uploads/2022/01/Comercio-Exterior-del-Libro-2020.pdf

- American Library Association
The state of America's libraries
Informe de l'estat de les biblioteques d'Amèrica 2020