Stigmergy, self-organisation, and sorting in collective robotics, Owen Holland and Chris Melhuish, University of West of England, http://www.ias.uwe.ac.uk/pdf's/journalpaper.pdf
Algorithms for Building Annular Structures with Minimalist Robots Inspired by Brood Sorting in Ant Colonies, Matt Wilson, Chris Melhuish, Ana B. Sendova-Franks, Samuel Scholes, University of West of England, http://www.ias.uwe.ac.uk/pdf's/AutRobots_Wilson_etal_2.pdf
Robotic sorting and collection, C. Ronald Kube, Hong Zhang and Xiaohuan Wang. "Controlling Collective Tasks With An ALN," 1993 IEEE/RSJ International Conference on Intelligent Robots and Systems, pages 289-293: http://www.cs.ualberta.ca/~kube/research.html (videos also available here).
Termite nest construction: http://www.comp.leeds.ac.uk/danl/cconstruct.html
Collective and Swarm Intelligence in natural and artificial systems, Andres Perez-Uribe: http://www.geocities.com/fastiland/Teaching/acs/swarm.html
Special issue of Artificial Life on Stigmergy: http://0-www.mitpressjournals.org.wam.leeds.ac.uk/toc/artl/5/2
The use of Flocks to drive a Geographic Analysis Machine, James Macgill, Stan Openshaw: http://www.geocomputation.org/1998/24/gc24_01.htm
Web-based multi-agent spatial analysis tools, James Macgill, Stan Openshaw, and Ian Turton: http://www.geovista.psu.edu/sites/geocomp99/Gc99/069/gc_069.htm