Google gives these:
http://www.pnas.org/content/95/23/13755.full.pdf
http://www.icmp.lviv.ua/journal/zbirnyk.79/33001/art33001.pdf
http://www.complex-systems.com/pdf/19-4-4.pdf
https://editorialexpress.com/cgi-bin/conference/download.cgi?db_name=ASSET2007&paper_id=287
http://ms.mcmaster.ca/~rogern4/pdf/publications_2009/annie_ltm.pdf
http://210.26.51.93/chenlab/images/4/4e/025.pdf
Google gives these:
http://www.pnas.org/content/95/23/13755.full.pdf
http://www.icmp.lviv.ua/journal/zbirnyk.79/33001/art33001.pdf
http://www.complex-systems.com/pdf/19-4-4.pdf
https://editorialexpress.com/cgi-bin/conference/download.cgi?db_name=ASSET2007&paper_id=287
http://ms.mcmaster.ca/~rogern4/pdf/publications_2009/annie_ltm.pdf
http://210.26.51.93/chenlab/images/4/4e/025.pdf