Toivari, L., and O. Lindqvist. “Daily Singing Rhythmics of the Marsh Warbler (Acrocephalus Palustris) and Blyth´s Reed Warbler (Acrocephalus Dumetorum)”. Ornis Fennica, vol. 39, no. 4, Dec. 1962, pp. 151–154, https://ornisfennica.journal.fi/article/view/132678.