Report of the Select Committee on Intelligence, United States Senate on Russian Active Measures Campaigns and Interference in the 2016 U.S. Election; Volume 2: Russia's Use of Social Media with Additional Views (Redacted) [open pdf - 7MB]
From the Introduction: "In 2016, Russian operatives associated with the St. Petersburg-based Internet Research Agency (IRA) used social media to conduct an information warfare campaign designed to spread disinformation and societal division in the United States. [...] Masquerading as Americans, these operatives used targeted advertisements, intentionally falsified news articles, self-generated content, and social media platform tools to interact with and attempt to deceive tens of millions of social media users in the United States. This campaign sought to polarize Americans on the basis of societal, ideological, and racial differences, provoked real world events, and was part of a foreign government's covert support of Russia's favored candidate in the U.S. presidential election."
U.S. Senate Select Committee on Intelligence: https://www.intelligence.senate.gov/