@article{DMGT_1997_17_2_a4,
     author = {Broersma, Hajo and Li, Xueliang},
     title = {Spanning trees with many or few colors in edge-colored graphs},
     journal = {Discussiones Mathematicae. Graph Theory},
     pages = {259--269},
     publisher = {mathdoc},
     volume = {17},
     number = {2},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGT_1997_17_2_a4/}
}