OBERHAUSEN, B. Leserservice 2020 – Zahlen und Fakten. WLBforum, Stuttgart, v. 23, n. 1, p. 34–35, 2021. DOI: 10.53458/wlbf.v23i1.46. Disponível em: https://journals.wlb-stuttgart.de/ojs/index.php/wlbf/article/view/46. Acesso em: 20 jan. 2022.