There is no link that I know of. It's in one of his books.
It consists of a balsa body from a 1/2" square piece of balsa tapered in a conventional manner except the front surface is sloped back in a 45 degree angle instead of leaning forward like a regular popper. Against this flat, sloping surface you epoxy a piece of thin plastic as found in a hook container box with a centered hole for the hook eye to stick through. The piece of plastic also extends down below the bottom of the body to provide the "wiggle" blade as on a spinning lure. Please don't give me static about this being a lure and not being a fly. I've taken a lot of liberties with his exact design and they still wiggle nicely.