Luca Aceto Wan Fokkink Anna Ingólfsdóttir A Cook's Tour of Equational Axiomatizations for Prefix Iteration. 20-34 1998 conf/fossacs/1998 FoSSaCS http://link.springer.de/link/service/series/0558/bibs/1378/13780020.htm db/conf/fossacs/fossacs1998.html#AcetoFI98