DONNER, A.; PETRELIUS, A. Uppsökandet af den Rysk-Skandinaviska gradmätningens inom Finland belägna triangelpunkter. Fennia - International Journal of Geography, [S. l.], v. 1, n. 1, p. 1–38, 1889. Disponível em: https://fennia.journal.fi/article/view/154710. Acesso em: 18 dec. 2024.