Lothar, it is understandable that you might ask about the Martens connection. Martens worked for Salviati and Aureliano Toso. He is often accredited for some glass done by AVeM or Fratelli Toso. I have not found any convincing evidence that he designed anything for these companies. There are a couple of books that mention that a AVeM tutti-frutti piece was designed by Martens, but I've not heard any hard evidence.
Paperweights like the ones you show were done by AVeM and Fratelli Toso, as well as some other companies. FToso was so prolific that I think glasstrufflehunter is most likely right in what he wrote. Latticino scramble vases that are similar to this paperweight are often said to be designed by Martens on eBay, but they aren't, as far as I have been able to determine.
I usually don't write on the pwt group, but I couldn't resist this topic.