Visitors count! Guidance for protected areas on the economic analysis of visitation - Spenceley, Anna; Schagner, Jan; Engels, Barbara; Cullinane Thomas, Catherine; Engelbauer, Mauel; Erkkonen, Joel; Job, Hubert; Kajala, Liisa; Majewski, Lisa; Metzler, Daniel; Mayer, Marius; Rylance, Andrew; et al. (UNESCO, 2021)