Donner, A., and A. Petrelius. “Uppsökandet Af Den Rysk-Skandinaviska gradmätningens Inom Finland belägna Triangelpunkter”. Fennia - International Journal of Geography 1, no. 1 (January 1, 1889): 1–38. Accessed December 18, 2024. https://fennia.journal.fi/article/view/154710.