Gregersen, Håkon, and Finn Gregersen. “Old Bilberry Forest Increases Likelihood of Capercaillie Tetrao Urogallus Lek Occupancy in Southern Norway”. Ornis Norvegica 31 (January 1, 2008): 105-115. Accessed February 22, 2020. https://boap.uib.no/index.php/ornis/article/view/172.