DOI: 10.1007/0-387-24270-8_2
Full citation:
Otte, M. (2005)., Mathematics, sign and activity, in M. H. G. . Hoffmann, J. Lenhard & F. Seeger (eds.), Activity and sign, Dordrecht, Springer, pp. 9-22.
This document is unfortunately not available for download at the moment.