@article{10_1090_S0894_0347_99_00295_7,
     author = {Fomin, Sergey and Zelevinsky, Andrei},
     title = {Double {Bruhat} cells and total positivity},
     journal = {Journal of the American Mathematical Society},
     pages = {335--380},
     publisher = {mathdoc},
     volume = {12},
     number = {2},
     year = {1999},
     doi = {10.1090/S0894-0347-99-00295-7},
     url = {http://geodesic.mathdoc.fr/articles/10.1090/S0894-0347-99-00295-7/}
}