Ubipay: conducting everyday payments with minimum user involvement. - Vili Lehdonvirta; Hayuru Soma; Hitoshi Ito; Hiroaki Kimura; Tatsuo Nakajima (CHI Extended Abstracts, 2008)

Applying pervasive technologies to create economic incentives that alter consumer behavior. - Tetsuo Yamabe; Vili Lehdonvirta; Hitoshi Ito; Hayuru Soma; Hiroaki Kimura; Tatsuo Nakajima (UbiComp, 2009)

UbiPay: minimizing transaction costs with smart mobile payments. - Vili Lehdonvirta; Hayuru Soma; Hitoshi Ito; Tetsuo Yamabe; Hiroaki Kimura; Tatsuo Nakajima (Mobility Conference, 2009)

Activity-Based Micro-pricing: Realizing Sustainable Behavior Changes through Economic Incentives. - Tetsuo Yamabe; Vili Lehdonvirta; Hitoshi Ito; Hayuru Soma; Hiroaki Kimura; Tatsuo Nakajima (PERSUASIVE, 2010)