BBC News - Afghan helicopter crash kills 31 US troops(нявызн.). bbc.co.uk (6 жніўня 2011). — «incident is believed to be the biggest single loss of life for US forces in Afghanistan since they began operations in 2001.» Архівавана з першакрыніцы 25 лютага 2012. Праверана 6 August 2011.
BBC News - Afghan helicopter crash kills 31 US troops(нявызн.). bbc.co.uk (6 жніўня 2011). — «incident is believed to be the biggest single loss of life for US forces in Afghanistan since they began operations in 2001.» Архівавана з першакрыніцы 25 лютага 2012. Праверана 6 August 2011.