I think Springhead is being a bit harsh on Pina. I've got six Pina books and I'd be lost without them. The Fifities book had some problems, but, as far as I can make out, she corrected them in Italian Glass, which shows glass I can actually afford to buy, and in the Seguso and Toso books. Her Scandinavian books are essential to me, again as the other books tend to show only glass way out of my price range and are narrowly focussed. I'd love to have a full range of catalogues from Scandinavia, but until that happens, I'll rely on Pina. She's also a very good person to deal with, BTW, although I've not had a great deal of contact with her. I would hesitate to say she's wrong, as, as Laura says, likely more than one company produced these hats. I would imagine Skinner agreed with the attribution, or vice versa.
It's interesting to compare the pictures (from the Pina book and from Springhead) side by side, as Springhead did with the elephants. Which one do people prefer?