Anni Karhumaa Kalle Piirainen Kalle Elfvengren Markku Tuominen Assessment of Facilitators' Design Thinking. 231-246 2009 CRIWG http://dx.doi.org/10.1007/978-3-642-04216-4_19 conf/criwg/2009 db/conf/criwg/criwg2009.html#KarhumaaPET09