Svetlana Yarosh Kevin Huang Ian Mosher Marisa Topping Playware: augmenting natural play to teach sign language. 3249-3254 2008 CHI Extended Abstracts http://doi.acm.org/10.1145/1358628.1358839 conf/chi/2008a db/conf/chi/chi2008a.html#YaroshHMT08