Corregidor-Castro, Alejandro, Thomas E. Holm, and Thomas Bregnballe. “Counting Breeding Gulls With Unmanned Aerial Vehicles: Camera Quality and Flying Height Affects Precision of a Semi-Automatic Counting Method”. Ornis Fennica 98, no. 1 (March 31, 2021): 33–45. Accessed April 3, 2025. https://ornisfennica.journal.fi/article/view/133979.