R. Munafo, 2017) slide rule made at the age of 14, 2017.

, Abacus from Upper Italy (1340) German Historical Museum

G. Pinthus, , 1950.

F. Flexowriter, , 2017.

, Picture from Collection Jak Boumans (2017) downloaded August27, 2013.

D. M. Vyas, A. Nijholt, and G. C. Van-der-veer, Supporting cooperative design through "living" artefacts, Proceedings of the 6th Nordic Conference on Human-Computer Interaction Extending Boundaries, NordiCHI '10, pp.541-550, 2010.
DOI : 10.1145/1868914.1868975