@article{HellwigVolkmann2013,
  author    = {Angelika Hellwig and Lutz Volkmann},
  title     = {Maximally edge-connected digraphs},
  journal   = {Australasian journal of combinatorics},
  volume    = {Vol. 27},
  pages     = {23 -- 32},
  year      = {2013},
}