Looking for literature

[Uilleag]

I have some copies of the Sir Fitzralph effigy, as well as the artist's interpretation of this harness, but I am looking for any written research on this particular harness. I am looking for specific reference to the polyens. How they were constructed, materials thought to have been used etc.

My library is very limited, so pointing to reference material where I might find what I am looking for would be helpful. It will also give me an excuse to expand my research library.

Thanks for any help.