  We derive the low-energy effective action for the spinning (GKP) string in
AdS(3) x S(3) x M(4) where M(4) = S(3) x S(1) or T(4). In the first case the
action consists of two O(4) non-linear sigma models which are coupled through
their interaction with four massless Majorana fermions (plus one free decoupled
scalar). While in the second case it consists of one O(4) sigma model coupled
to four Majorana fermions together with four free scalars from the T(4). We
show that these models are classically integrable by constructing their Lax
connections.
