"Arctic Monday for 140 million as 'POLAR VORTEX' barrels across the US: 4,400 flights canceled, schools closed as far south as ATLANTA and the coldest temperatures recorded in 20 years".
Truy cập ngày 6 tháng 1 năm 2014.  ^ “Arctic Monday for 140 million as 'POLAR VORTEX' barrels across the US: 4,400 flights canceled, schools closed as far south as ATLANTA and the coldest temperatures recorded in 20 years”.