Being frank, I didn't even realize this was available freely. When I searched "Miski silphium" the first place I ran across was asking for a log in (researchgate I believe) so I just copied the DOI since its easier for folks... PTSD from reading a lot of papers I guess. IYKYK
Anyways I first read about this in a book: The Lost Supper by Taras Grescoe. I also recommend checking that book out if you find this topic interesting.
I guess that's useful for people who aren't able to access the article itself in the standard ways, being that it doesn't seem to be paywalled at all.