Bjorn Wiemer, Dialect and language contacts on the territory of the Grand Duchy from the 15th century until 1939, Kurt Braunmüller, Gisella Ferraresi, Aspects of multilingualism in European language history, John Benjamins Publishing Company, 2003, ISBN 90-272-1922-2, Google Print, p.109; 125.
Letukienė, N., Istorija. Politologija: kurso santrauka istorijos egzaminui, 2003, p. 182. There can be found also different numbers, for example: Kevin O'Connor, The history of the Baltic States, Greenwood Publishing Group, 2003, ISBN 0-313-32355-0, Google Print, p.17.. Here author estimates that there were 9 million inhabitants in GDL, and 1 million of them were ethnic Lithuanians by 1387.
Jarmo Kotilaine, Russia's foreign trade and economic expansion in the seventeenth century: windows on the world, BRILL, 2005, ISBN 90-04-13896-X, Google Print, p.45.
UNESCO, Audio-visual resources (archiviato dall'url originale il 28 dicembre 2011).. Retrieved 2011-09-12.
Department of Statistics to the Government of the Republic of Lithuania. Copia archiviata, su osp.stat.gov.lt. URL consultato il 15 marzo 2022 (archiviato dall'url originale l'8 ottobre 2014).. 2013-03-15.
Government of the Republic of Lithuania, The Official Gateway of Lithuania, Education System. URL consultato il 15 marzo 2022 (archiviato dall'url originale il 5 novembre 2013).
