Donatella Merlini Renzo Sprugnoli M. Cecilia Verri The Area Determined by Underdiagonal Lattice Paths. 59-71 1996 conf/caap/1996 CAAP db/conf/caap/caap96.html#MerliniSV96 http://dx.doi.org/10.1007/3-540-61064-2_29