A record-breaking low ice cover over the Great Lakes during winter 2011/2012: combined effects of a strong positive NAO and La Niña - Xuezhi Bai; Jia Wang; Jay Austin; David J. Schwab; Raymond Assel; Anne Clites; John F. Bratton; Marie Colton; John Lenters; Brent Lofgren; Trudy Wohlleben; Sean Helfrich; et al. (Climate Dynamics, 2015)