Michael Bernstein Desney S. Tan Greg Smith Mary Czerwinski Eric Horvitz Collabio: a game for annotating people within social networks. 97-100 2009 UIST http://doi.acm.org/10.1145/1622176.1622195 conf/uist/2009 db/conf/uist/uist2009.html#BernsteinTSCH09