None
Organisation for the Prevention of Chemical Weapons (OPCW), “Report of the Fact-Finding Mission Regarding the Incident of Alleged Use of Toxic Chemicals as a Weapon in Douma, Syrian Arab Republic, on 7 April 2018” (1 March 2019), https://www.opcw.org/sites/default/files/documents/2019/03/s-1731-2019%28e%29.pdf
Robin Mills, “Syria's pipeline gas theory is a low-budget drama,” National (25 September 2016), cited in Ahmed, 116.
Sami Moubayed, “Syrian-Saudi ties spiral downwards,” Asia Times Online (11 August 2011), https://web.archive.org/web/20170506080725/http:/www.atimes.com/atimes/Middle_East/MH11Ak02.html; “Qatari emir voices Qatar's support for Syria,” Now (3 April 2011), https://now.mmedia.me/lb/en/nownews/qatari_emir_voices_qatars_support_for_syria
Edward Yeranian, “Energy Rivalries Exacerbate Tensions in the Middle East,” VOA News (25 March 2017), https://www.voanews.com/a/energy-rivalries-exacerbate-tensions-middle-east/3781864.html, cited in Ahmed, 117.