Kristina Groth Cristian Bogdan Sinna Lindquist Yngve Sundblad Simple and playful interaction for informal communication and learning. 191-208 2007 3 Int. J. Knowledge Learning 2/3 http://dx.doi.org/10.1504/IJKL.2007.015550 db/journals/ijkl/ijkl3.html#GrothBLS07