Helmer Pedersen, Erik. 1983. “Keijo Virtanen: Settlement or Return. Finnish Emigrants (1860-1930) in the International Overseas Migration Movement. Migration Studies C 5. Turku, The Migration Institute, 1979. 275 S”. Historisk Tidsskrift 14 (januar). https://tidsskrift.dk/historisktidsskrift/article/view/52598.