Giusi Castiglione Andrea Frosini Emanuele Munarini Antonio Restivo Simone Rinaldi Combinatorial aspects of L-convex polyominoes. 1724-1741 2007 28 Eur. J. Comb. 6 http://dx.doi.org/10.1016/j.ejc.2006.06.020 db/journals/ejc/ejc28.html#CastiglioneFMRR07