@article{CMH_1994__69_4_140356,
     author = {Nanhua Xi},
     title = {Root vectors in quantum groups.},
     journal = {Commentarii mathematici Helvetici},
     pages = {612--639},
     publisher = {mathdoc},
     volume = {69},
     number = {4},
     year = {1994},
     zbl = {0822.17006},
     url = {http://geodesic.mathdoc.fr/item/CMH_1994__69_4_140356/}
}