1. The structure of Sperner k-families;Greene;J. Combin. Theory,1976
2. M. Saks, personal communication.
3. Parameters of partial orders and graphs: packing, covering, and representation;West,1985
4. D.B. West, “Polyunsaturated posets:” The Greene-Kleitman theorem is best possible. J. Combin. Theory Ser. A, to appear.
5. Semiantichains and unichain coverings in products of partial orders;West;SIAM J. Disc. Alg. Meth.,1981