  The study of electron-positron collisions at center-of-mass energies
corresponding to charmonium production has reached new levels of sensitivity
thanks to experiments by the BES and CLEO Collaborations. Final states $\gamma
P$, where $P$ is a pseudoscalar meson such as $\pi^0$, $\eta$, and $\eta'$ can
arise either from charmonium decays or in the continuum through a virtual
photon: $e^+ e^- \to \gamma^* \to \gamma P$. Estimates of this latter process
are given at center-of-mass (c.m.) energies corresponding to the $J/\psi(1S)$,
$\psi(2S)$, and $\psi(3770)$ resonances.
