Albert, M.H., Aldred, R.E.L., Atkinson, M.D., Handley, C.C., Holton, D.A. and McCaughan, D.J. 2005. Sorting Classes. The Electronic Journal of Combinatorics. 12, 1 (Jun. 2005), R31. DOI:https://doi.org/10.37236/1928.