  We study the associated production of the $A^0$ neutral CP--odd Higgs boson
with a neutral gauge boson $Z$ as well as single production of $A^0$ via
$e^+e^- \to \nu_e {\bar\nu}_e A^0$ at the one loop level in the Minimal
Supersymmetric Standard Model (MSSM). We show that the MSSM cross--section may
be enhanced by light SUSY particles. Then we study the production processes
$e^+e^-\to H^0_iZ$, $H^0_i\nu_e\bar \nu_e$ and $H^0_iH^0_j$ in the context of
the MSSM with scalar-pseudoscalar mixing. In a given channel we show that the
cross--section for all i (=1,2,3) can be above 0.1 fb provided $M_{H_{2,3}}\la
300$ GeV. This should be detectable at a Next Linear Collider and would provide
evidence for scalar--pseudoscalar mixing.
