https://sgp.fas.org/crs/natsec/RL33110.pdf
https://rusi.org/commentary/russias-reach-exceeds-its-grasp-over-karabakh-conflict?utm_source=RUSI+Newsletter&utm_campaign=f8c06368b6-EMAIL_CAMPAIGN_2020_09_10_09_43_COPY_01&utm_medium=email&utm_term=0_0c9bbb5ef0-f8c06368b6-47711229
https://www.reuters.com/world/leaked-us-intel-document-claims-serbia-agreed-arm-ukraine-2023-04-12/
https://www.tni.org/files/publication-downloads/marketforces-report-tni-statewatch.pdf