Giusi Castiglione Andrea Frosini Antonio Restivo Simone Rinaldi A Tomographical Characterization of L-Convex Polyominoes. 115-125 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3429&spage=115 2005 conf/dgci/2005 DGCI db/conf/dgci/dgci2005.html#CastiglioneFRR05