Out of physics curiousity, can anyone point to any references on induced
vibrations in aircraft (or any other mechanical) structures associated
with or caused by parametrically induced induced *subharmonic* or
*parametric* oscillations?

["Parametric oscillation" = a phenomena well known in electronics and
optics, in which if a structure has natural resonances with resonant
frequencies f1 and f2, and the structure is then excited or "pumped"
with a periodic force at a "pump" frequency fp = f1 + f2, this can cause
coupled oscillations to occur and grow at the "signal" and "idler"
frequencies f1 and f2.]