scholarly article by Carsten Neßhöver et al published June 2016 in Biodiversity and Conservation
author: Ilse R. Geijzendorffer, Luis Santamaría, Isabel Sousa Pinto, Esther Carmen, Christoph Görg, Carsten Neßhöver, Heidi Wittmer, Marie Vandewalle, Josef Settele, Stefan Schindler, Katalin Török, Barbara Livoreil