Branets, Anna, and Ad Backus. “L2 Knowledge Facilitating L3 Learning: the Role of Russian Linguistic Factors in Understanding of Ukrainian by Estonians [K2 Oskus Soodustamas K3 Omandamist: Vene Keele Roll Eesti Keelt Esimese Keelena Kõnelejatel Ukraina Keele Mõistmises]”. Philologia Estonica Tallinnensis, no. 5, Nov. 2020, pp. 59-86, https://doi.org/10.22601/PET.2020.05.02.