Michael Vallance Stewart Martin Charles Wiz Paul van Schaik LEGO Mindstorms<sup>TM</sup> for informed metrics in virtual worlds. 159-162 2009 BCS HCI http://doi.acm.org/10.1145/1671011.1671029 conf/bcshci/2009 db/conf/bcshci/bcshci2009.html#VallanceMWS09