1. A general criterion for the existence of transversals;Aharoni;Proc. Lond. Math. Soc.,1983
2. J. Folkman, Transversals of infinite families with finitely many infinite members, Rand Corporation, Memorandum, RM-5676-RP, 1968.
3. On representatives of subsets;Hall;J. Lond. Math. Soc.,1935
4. Distinct representatives of subsets;Hall;Bull. Amer. Math. Soc.,1948
5. Transversal Theory;Mirsky,1971