Characterizing Geographic Variation in Well-Being Using Tweets. - H. Andrew Schwartz; Johannes C. Eichstaedt; Margaret L. Kern; Lukasz Dziurzynski; Richard E. Lucas; Megha Agrawal; Gregory J. Park; Shrinidhi K. Lakshmikanth; Sneha Jha; Martin E. P. Seligman; Lyle H. Ungar (ICWSM, 2013)