Yes. I found this paper which talks about it more http://www.sidthomas.net/pdf/paperpdfs/Thomas%20et%20al%20JofE.pdf http://www.sidthomas.net/pdf/paperpdfs/Thom

Yes. I found this paper which talks about it more http://www.sidthomas.net/pdf/paperpdfs/Thomas%20et%20al%20JofE.pdf http://www.sidthomas.net/pdf/paperpdfs/Thomas%20et%20al%20Jo... p34 talks about its constituent properties. Crucially no one is quite sure what the exact active component is