Deborah I. Fels Martin Gerdzhev Ellen Hibbard Abby Goodrum Jan Richards Jim Hardman Norma Thompson 492-501 2009 HCI (7) http://dx.doi.org/10.1007/978-3-642-02713-0_52 conf/hci/2009-7 db/conf/hci/hci2009-7.html#FelsGHGRHT09