  We give necessary conditions for a polynomial to be the Conway polynomial of
a two-bridge link. As a consequence, we obtain simple proofs of the classical
theorems of Murasugi and Hartley. We give a modulo 2 congruence for links,
which implies the classical modulo 2 Murasugi congruence for knots. We also
give sharp bounds for the coefficients of the Conway and Alexander polynomials
of a two-bridge link. These bounds improve and generalize those of Nakanishi
and Suketa.
