This 19 July 2006 article from the internal NSA newsletter Foreign Affairs digest explains the ramifications of the Soviet attack on Korean Airlines flight 007 in 1983 for US-Japanese intelligence cooperation: see the Intercept article Japan Made Secret Deals With The NSA That Expanded Global Surveillance, 24 April 2017.
This post from internal NSA newsletter SIDToday dated 5 July 2003 describes how the agency utilised medical SIGINT to gain insights into the impact of China’s SARS outbreak that year, including details of the partner agencies NSA collaborated with: see the Intercept article How the U.S. Spies on Medical Nonprofits and Health Defenses Worldwide, 10 August 2016.
This internal document prepares for a visit of senior officers from Germany’s BND: see the Der Spiegel article New NSA Revelations: Inside Snowden’s Germany File, 18 June 2014.
This April 2013 agenda prepares for a visit of senior officials from the German BND. Subjects to be disussed include Special Source Operations: see the Der Spiegel article New NSA Revelations: Inside Snowden’s Germany File, 18 June 2014.