https://int.nyt.com/data/documenttools/house-antitrust-report-on-big-tech/b2ec22cf340e1af1/full.pdf
https://sipri.org/sites/default/files/2017-09/yb17-summary-eng.pdf
http://www.case-research.eu/files/?id_plik=5223
https://ecfsapi.fcc.gov/file/109303096909269/Sage%20&%20Carpenter,%202009.pdf