1. An inequality for the weights of two families of sets, their unions and intersections;Ahlswede;Z. Wahrscheinlichkeitstheor. Verwandte Geb.,1978
2. More on the generalized Macaulay theorem II;Clements;Discrete Math.,1977
3. Sperner Theory;Engel,1997
4. K. Engel, U. Leck, Optimal antichains and ideals in Macaulay posets, in: L. Lovász, A. Gyárfás, G.O.H. Katona, A. Recski, L. Székely (Eds.), Graph Theory and Combinatorial Biology, in: Bolyai Soc. Math. Stud., vol. 7, Budapest, 1999, pp. 199–222.