Berend, Daniel and Harmse, Jørgen E., On some arithmetical properties of middle binomial coefficients. Acta Arith. 84 (1998), no. 1, 31-41, doi:10.4064/aa-84-1-31-41.

T. F. Bloom and E. Croot, Integers with small digits in multiple bases. arXiv:2509.02835 (2025).

Erdős, P. and Graham, R. L. and Ruzsa, I. Z. and Straus, E. G., On the prime factors of $(\sp{2n}\sb{n})$. Math. Comp. (1975), 83-92.

Guy, Richard K., Unsolved problems in number theory. Third edition, Problem Books in Mathematics, Springer, New York (2004), xviii+437 pp.; doi:10.1007/978-0-387-26677-0. Section B33 "Largest divisor of a binomial coefficient", printed p. 135, reports Graham's offer, the base 3, 5 and 7 digit conditions and the 14 known values below $7^{10}$. The amount of the offer is in conflict: Guy prints an amount different from the one the site attributes to [Gu04] and [BeHa98]; Berend and Harmse (Section 4, from a personal communication of Graham) and Pomerance [Po15c] (Section 4) both print the site's amount. Library home: Guy 2004.

Pomerance, Carl, Divisors of the middle binomial coefficient. Amer. Math. Monthly (2015), 636-644.