Polans (eastern) (English Wikipedia)

Subtelny, Orest (10 November 2009). "The Rise and Decline of Kievan Rus". Ukraine: A History (4 ed.). University of Toronto Press (published 2009). ISBN 9781442697287. Retrieved 16 April 2022. After conquering Kiev in 882 and establishing control over the Polianians, [Oleh] forcefully extended his authority [...] over the surrounding tribes [...]

doi.org (Global: 2^nd place; English: 2^nd place)

Turchin 2009, pp. 191–217; "The Khazars also subjugated East Slavic groups, such as the Polanians, and forced others to pay tribute." Turchin, Peter (2009). "A theory for formation of large empires" (PDF). Journal of Global History. 4 (2). Cambridge University Press: 191–217. doi:10.1017/S174002280900312X. S2CID 73597670.
Motsia, Oleksandr (2009). «Руська» термінологія в Київському та Галицько-Волинському літописних зводах ["Ruthenian" question in Kyiv and Halych-Volyn annalistic codes] (PDF). Arkheolohiia (1). doi:10.6084/M9.FIGSHARE.1492467.V1. ISSN 0235-3490. Archived (PDF) from the original on 2 February 2014. Retrieved 25 January 2023.

Turchin 2009, pp. 191–217; "The Khazars also subjugated East Slavic groups, such as the Polanians, and forced others to pay tribute." Turchin, Peter (2009). "A theory for formation of large empires" (PDF). Journal of Global History. 4 (2). Cambridge University Press: 191–217. doi:10.1017/S174002280900312X. S2CID 73597670.

Turchin 2009, pp. 191–217; "The Khazars also subjugated East Slavic groups, such as the Polanians, and forced others to pay tribute." Turchin, Peter (2009). "A theory for formation of large empires" (PDF). Journal of Global History. 4 (2). Cambridge University Press: 191–217. doi:10.1017/S174002280900312X. S2CID 73597670.