@article{10_1090_S0894_0347_03_00441_7,
     author = {Knutson, Allen and Tao, Terence and Woodward, Christopher},
     title = {The honeycomb model of {\ensuremath{\mathit{G}}\ensuremath{\mathit{L}}_{\ensuremath{\mathit{n}}}(\ensuremath{\mathbb{C}})} tensor products {II:} {Puzzles} determine facets of the {Littlewood-Richardson} cone},
     journal = {Journal of the American Mathematical Society},
     pages = {19--48},
     year = {2004},
     volume = {17},
     number = {1},
     doi = {10.1090/S0894-0347-03-00441-7},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-03-00441-7/}
}