Leppänen, Jaakko Johannes, and Jan Weckström. “Varying Degradation of Subfossil Daphnia Longispina During the past 250 Years and the Discovery of Fossil Helmet-Type Head Shields: Preliminary Results”. Advances in Oceanography and Limnology 7, no. 2 (November 25, 2016). Accessed April 26, 2024. https://www.pagepressjournals.org/aiol/article/view/6293.