%0 Journal Article %A Kyungyong Lee %A Li Li %A Matthew R. Mills %T A Combinatorial Formula for Certain Elements of Upper Cluster Algebras %J Symmetry, integrability and geometry: methods and applications %D 2015 %V 11 %U http://geodesic.mathdoc.fr/item/SIGMA_2015_11_a48/ %G en %F SIGMA_2015_11_a48