Lorenz Huelsbergen Edward A. Rietman Robert Slous Evolution of Astable Multivibrators <i>in Silico</i>. 66-77 http://link.springer.de/link/service/series/0558/bibs/1478/14780066.htm 1998 conf/ices/1998 ICES db/conf/ices/ices1998.html#HuelsberbenRS98