Iker Azpeitia Jesús Ibáñez Spontaneous Emergence of Robust Cellular Replicators. 132-143 2002 conf/acri/2002 ACRI http://link.springer.de/link/service/series/0558/bibs/2493/24930132.htm db/conf/acri/acri2002.html#AzpeitiaI02