  The purpose of the current Letter is to give some relations between
gravitational lensing in the strong-deflection limit and the frequencies of the
quasinormal modes of spherically symmetric, asymptotically flat black holes. On
the one side, the obtained relations can give a physical interpretation of the
strong-deflection limit parameters. On the other side, they also give an
alternative method for the measurement of the frequencies of the quasinormal
modes of spherically symmetric, asymptotically flat black holes. They could be
applied to the localization of the sources of gravitational waves and could
tell us what frequencies of the gravitational waves we could expect from a
black hole acting simultaneously as a gravitational lens and a source of
gravitational waves.
