-Official sources-
CIA, FBI, and NSA: "Assessing Russian Activities and Intentions in Recent US Elections” -- January, 2017 declassified report (PDF)
FBI and DHS: "GRIZZLY STEPPE – Russian Malicious Cyber Activity" -- December, 2016 declassified technical report
Congressman Eric Swalwell (House Intelligence Committee): "Protect Our Democracy" -- context for the Russia investigation in the House, periodically updated
Full transcript: FBI Director James Comey testifies on Russian interference in 2016 election -- March 20th, 2017 House Intelligence Committee hearing, also includes testimony from NSA Director
Senate Intelligence Committee Open Hearing: Disinformation: A Primer in Russian Active Measures and Influence Campaigns 10AM Session -- March 30th, 2017. Includes testimony of Clinton Watts. Continues with 2PM Session
Full transcript: Sally Yates and James Clapper testify on Russian election interference -- May 8th, 2017 Senate Judiciary Committee hearing
CSPAN Video and transcript for testimony of former CIA Director John Brennan on Russian election interference -- May 23rd, 2017 House Intelligence Committee hearing
-Summaries by journalists-
Massimo Calabresi (TIme Magazine): "Inside Russia’s Social Media War on America" -- Goals and methods of the Russian active measures campaign
Joe Uchill (The Hill): "Five reasons intel community believes Russia interfered in election" -- summary of the evidence for Russian involvement in hacking of DNC and John Podesta
Phillip Bump (Washington Post): "Timeline: What we know about Trump’s campaign, Russia and the investigation of the two" -- places information about interactions between the Trump team and Russia in chronological order
Hannah Levintova (Mother Jones): "The Long, Twisted, and BIzzarre history of the Trump-Russia Scandal" -- constantly updating timeline of developments
Marshall Cohen and Tal Yellin (CNN): "The Many Paths from Trump to Russia" -- interactive diagram mapping the personal and financial connections between Russia and members of Trump's team
Bonnie Berkowitz, Denise Lu and Julie Vitkovskaya (Washington Post): "Here’s what we know so far about Team Trump’s ties to Russian interests" -- another interactive Trump-Russia diagram
-Link collections assembled by other interested amateurs-
Chris LeMay West: "From Russia, With Love" -- fairly comprehensive
Raul Gutierrez: "Trump's Russian Connections, a Handy TImeline" -- in reverse chronological order
Thomas Wood: "RussiaGate" -- Very long Google Docs file with many links