Janlert, L-E., & Stolterman, E. (in progress). Increasing Interactivity.
Janlert, L-E., & Stolterman, E. (forthcoming). Faceless Interaction - a conceptual examination of the notion of interface: past, present and future. In Human-Computer Interaction. (will hopefully be available soon)
Lars-Erik Janlert and Erik Stolterman. 2010. Complex interaction. ToCHI (ACM Transactions of Computer-Human Interaction) 17, 2.
Janlert, L-E. & Stolterman, E. (1997). The character of things. in Design Studies Vol 18, No 3, July (1997).
The plan now is to develop these articles into a book. We are convinced that the field of HCI need our book :-) There is a need for an in-depth and detailed attempt at defining what interactivity is and can be.