Help documentation of polarimetric parameters

I want compute some polarimetric parameters using the operator Polarimetric parameters in SNAP. there are many different parameters including Use Mean Matrix, Span, Pedestal Height, Radar Vegetation Index, Radar Forest Degradation Index, Canopy Structure Index, Volume Scattering Index, Biomass Index and so on, but I can not find the help documentation about these parameters. Where I can find these relevant help documentations or papers?

please don’t start new topics on existing questions.