@article{ThomasWieder2004b,
  author = {Sloane, N. J. A. and Wieder, T.},
  doi = {10.1007/s11083-004-9460-9},
  interhash = {85a1f6a9c0fe5adf52ca0064af855da2},
  intrahash = {c5f9fa23e60df42f12e1d9bdfef7581f},
  journal = {Order},
  number = 1,
  pages = {83--89},
  title = {The Number of Hierarchical Orderings},
  volume = 21,
  year = 2004
}