Dual polarimetric H-A-Alpha decomposition

Hello. I need article or source for the dual polarimetry decomposition in snap6.

I’m not sure if one of those is the original source but you will surely find it pointed out in the references in these articles

thank you.

If you find the original source in one of these articles, it would be nice if you let us know so others who have the same question in the future can find an answer here.