H. de Garis. ECAL-93 Self organisation and life: from simple rules
to global complexity, page 274--284. CP 231, Universite Libre de Bruxelles, Bld. du
Triomphe, 1050 Brussels, Belgium, Fax 32-2-659.5767
Phone 32-2-650.5776 Email sgross@ulb.ac.be, (24--26 May 1993)