This NSA presentation from 24 June 2009 explains how to use the email search functionality within XKeyScore: see the Intercept article XKEYSCORE: NSA’s Google for the World’s Private Communications, 1 July 2015.

This NSA classification guide, dated 21 November 2011, covers signals intelligence material that as to be kept secret for more than the standard 60 years: see the Der Spiegel article The NSA in Germany: Snowden’s Documents Available for Download, 18 June 2014.

This undated internal NSA document illustrates the degrees of cooperation in the agency’s relationships with different foreign powers. “Tier A” and “Tier B” are elsewhere referred to as Second and Third Parties: see the book No Place To Hide, 13 May 2014.

This 24 February 2005 article from the internal NSA newsletter Foreign Affairs Digest describes third party cooperation and interoperability in High Frequency Direction-Finding (HFDF): see the Intercept article Japan Made Secret Deals With The NSA That Expanded Global Surveillance, 24 April 2017.

This undated NSA presentation sets out the network-mapping tool Treasure Map, and supplies information on some of the agency’s collection access points: see the Intercept article New Zealand Launched Mass Surveillance Project While Publicly Denying It, 15 September 2014.

Within 45 minutes, the NSA was able to relay a tip to the Austrian intelligence service about a possible terrorist carrying explosives on a bus headed from Bosnia to Austria.

This 2010 NSA presentation describes Project Camberdada, an attempt to subvert popular antivirus software by means of surveilling email traffic: see the Intercept article Popular Security Software Came Under Relentless NSA and GCHQ Attacks, 22 June 2015.

This slide, taken from the NSA’s annual review of its cooperation with foreign partners, shows an expansion in the agency’s international relationships: see the book No Place To Hide, 13 May 2014.

An intelligence analyst inquires whether the Special Collection Service will be hiring more intelligence analysts in their field sites around the globe; SCS responds that they have a limited number of openings for that position.

The U.S. closed a number of High Frequency Direction-Finding sensor sites in the 1990s. To ensure they're able to track signals in areas that had previously been covered by now-shuttered stations, the Signals Intelligence Directorate worked with Second and Third Party partners to share resources and establish a global direction-finding network.

An NSA couple worked at locations in Germany’s Rheinland and enjoyed local cuisine and European travel.