Advance Integral Equation model for soil scatter

I am study the radar backscattering about the vegetation and soil, and the Advance Integral Equation model (AIEM) is a commonly used model for the research of radar backscattering.I hava read many paper ,but ,I couldn’t found the complete codes about this model.
So where I can find the code for Integral Equation Model or Advance Integral Equation Model.
thanks for your help and advice。

At his point you have most likely found the needed information. I came by a doctoral thesis covering use of few different backscattering models. It describes necessary steps needed in implementation of IEM-, X-bragg-, Oh- and Dubois-model.

Habib Mazaheri Tehrani (2014) Soil Moisture Estimation with Polarimetric SAR Data:;jsessionid=E74DF0ECD432705FD8E72718D628ECC2?sequence=2

This may work … not sure