Lee, Chang Hee, Lockton, Dan and Kim, Ji Eun, 2018, Book Section, Exploring Cognitive Playfulness Through Zero Interactions In: Koskinen, Ilpo and Lim, Youn-kyung, (eds.) DIS '18 Companion Proceedings of the 2018 ACM Conference Companion Publication on Designing Interactive Systems. ACM Press, NY, USA, pp. 63-67. ISBN 978-1-4503-5631-2