Kalev, Leif, and Rein Ruutsoo. “Kodakondsus Ja Mitmikkodakondsus Euroopastuvas Eestis”. Acta Politica Estica, no. 3, Sept. 2009, pp. 176-17, https://publications.tlulib.ee/index.php/actapolitica/article/view/553.