Litwiniak, K., and M. Przymencki. “Long-Eared Owl Asio Otus Breeding in a Caspian Gull Larus Cachinnans Colony: Reversed Roles in Protective Nesting Association?”. Ornis Svecica, vol. 30, Dec. 2020, pp. 73–78, doi:10.34080/os.v30.22033.