Four-way balanced designs based on Youden squares with 5, 6, or 7 treatments.

@article{Clarke1967FourwayBD,
  title={Four-way balanced designs based on Youden squares with 5, 6, or 7 treatments.},
  author={Geraldine M. Clarke},
  journal={Biometrics},
  year={1967},
  volume={23 4},
  pages={803-12}
}