@article{10_37236_115,
     author = {Norbert Seifter and Vladimir I. Trofimov},
     title = {Reachability relations and the structure of transitive digraphs},
     journal = {The electronic journal of combinatorics},
     year = {2009},
     volume = {16},
     number = {1},
     doi = {10.37236/115},
     zbl = {1178.05051},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/115/}
}