ZEPP, H. Regional green belts in the Ruhr region. A planning concept revisited in view of ecosystem services. ERDKUNDE, [S. l.], v. 72, n. 1, p. 1–21, 2018. DOI: 10.3112/erdkunde.2018.01.01. Disponível em: https://journals-test.ulb.uni-bonn.de/index.php/erdkunde/article/view/2823. Acesso em: 11 dec. 2024.