Esparza, B., A. Martínez-Abraín, S. Merino, and D. Oro. 2004. “Immunocompetence and the Prevalence of Haematozoan Parasites in Two Long-Lived Seabirds”. Ornis Fennica 81 (1):40–46. https://ornisfennica.journal.fi/article/view/133611.