Tatsuyuki Kawamura Tomohiro Fukuhara Hideaki Takeda Yasuyuki Kono Masatsugu Kidode Ubiquitous Memories: a memory externalization system using physical objects. 287-298 2007 11 Personal and Ubiquitous Computing 4 http://dx.doi.org/10.1007/s00779-006-0085-4 db/journals/puc/puc11.html#KawamuraFTKK07