Ottvall, Richard, and Jan Pettersson. 1998. “Is There a Viable Population of Corncrakes Crex Crex on Öland, Southeastern Sweden?: Habitat Preference in Relation to Hay-Mowing Activities”. Ornis Svecica 8 (4). Lund, Sweden:157-66. https://doi.org/10.34080/os.v8.22940.