1. Aleksandrova, V. (2017). Latviyskoe obshchestvo privetstvovalo vhozhdenie strany v sostav SSSR. Rubaltic.ru. Retrieved October 29, 2020, from https://www.rubaltic.ru/article/kultura-i-istoriya/15122017-latviyskoe-obshchestvo-privetstvovalo-vkhozhdenie-strany-v-sostav-sssr/.
2. Andriukaitis, L. (2020). Russian propaganda efforts in the Baltics and the wider Region. Vilnius Institure for Policy Analysis. Retrieved October 9, 2020, from https://vilniusinstitute.lt/wp-content/uploads/2020/05/VIPA_Andriukaitis_2020_Iv4-1%D0%B5.pdf.
3. Annual Review of the Estonian Internal Security Service 2007 (2007). Tallinn.
4. Annual Review 2014 of Estonian Internal Security Service (2014). Tallinn.
5. Apryshchenko, V. (2016). Pamyat ‘kak bezopasnost’. Novoe proshloe, 3, 86–108. https://doi.org/10.18522/2500-3224-2016-3-86-108.