Barry Guiduli András Gyárfás Stéphan Thomassé Peter Weidl 2-Partition-Transitive Tournaments. 181-196 1998 72 J. Comb. Theory, Ser. B 2 http://dx.doi.org/10.1006/jctb.1997.1806 db/journals/jct/jctb72.html#GuiduliGTW98