Alberto Del Lungo Andrea Frosini Simone Rinaldi ECO Method and the Exhaustive Generation of Convex Polyominoes. 129-140 2003 conf/dmtcs/2003 DMTCS http://link.springer.de/link/service/series/0558/bibs/2731/27310129.htm db/conf/dmtcs/dmtcs2003.html#LungoFR03