Ido, S. “Vowel Alternation in Disyllabic Reduplicatives: An Areal Dimension”. Eesti Ja Soome-Ugri Keeleteaduse Ajakiri. Journal of Estonian and Finno-Ugric Linguistics, vol. 2, no. 1, Dec. 2011, pp. 185-94, doi:10.12697/jeful.2011.2.1.12.