STOYANOVA, A.; BERBEROVA, R. Educational ecotourism in Bulgaria - opportunities to expand good practices. Annual of Natural Sciences Department, [S. l.], v. 9, p. 1–12, 2024. DOI: 10.33919/ansd.24.9.1. Disponível em: https://ojs.nbu.bg/index.php/ANSD/article/view/1162. Acesso em: 7 dec. 2025.