  We study one and two hole properties of the t-J model at half-filling on the
square lattice using series expansion methods at T=0. The dispersion curve for
one hole excitations is calculated and found to be qualitatively similar to
that obtained by other methods, but the bandwidth for small $t/J$ is some 20%
larger than given previously. We also obtain the binding energy and dispersion
relation for two hole bound states. The lowest bound state as $t/J$ increases
is found to be first d-wave, and then p-wave, in accordance with predictions
based upon the Kohn-Luttinger effect. We also make a similar study for the
$t-J_z$ model.
