@article{CMJ_2009_59_3_a8,
     author = {Shao, Yanling and Gao, Yubin},
     title = {Exponents of two-colored digraphs},
     journal = {Czechoslovak Mathematical Journal},
     pages = {655--685},
     year = {2009},
     volume = {59},
     number = {3},
     mrnumber = {2545648},
     zbl = {1224.15020},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMJ_2009_59_3_a8/}
}