LetterSampo Finland (1809-1917) Data Service and Portal: Searching, Exploring, and Analyzing Historical Letters and Their Underlying Networks. - Eero Hyvönen; Petri Leskinen; Henna Poikkimäki; Heikki Rantala; Jouni Tuominen; Senka Drobac; Ossi Koho; Ilona Pikkanen; Hanna-Leena Paloposki (ESWC (Satellite Events), 2025)