simple window glass question

Oh, I have to add.. I said this is a report by the Leuven University, but Eric Desart pointed out to me that the report I name does not contain this information. I got a photocopy with named report in front and it looked all one report, but it turned out to be a compilation, maybe from a lecture or something. Gonna send Eric a copy, maybe he finds out the real source.... I'm sure it all is certified information, not bullshit. Bert