1. Some problems in combinatorial number theory;Anderson,1967
2. Combinatorics of Finite Sets;Anderson,1987
3. On the set of divisors of a number;deBruijn;Nieuw Arch. Wisk.,1952
4. On a problem of Rota;Canfield;Adv. Math.,1978
5. Matchings in the partition lattice;Canfield;SIAM J. Discrete Math.,1993