Radiatively induced neutrino Majorana masses and oscillation

We review and remark on models of radiatively induced neutrino Majorana masses and oscillations. It is pointed out that while the models are capable of accounting for the observed solar and atmospheric neutrino oscillation, some of them can also induce neutrinoless double beta decay and $\mu^-$ -- $e^+$ conversion in nuclei large enough to be potentially observable in the near future.