Jensen, B. (1978) “William R. Copeland: The Uneasy Alliance. Collaboration between the Finnish Opposition and the Russian Underground. 1899-1904. Suomalaisen Tiedeakatemian Toimituksia ser. B torn. 179. Helsinki, 1973. 224 s. FM 33.”, Historisk Tidsskrift, 130. Tilgængelig hos: https://tidsskrift.dk/historisktidsskrift/article/view/52024 (Set: 20november2019).