In looking at the piece, IMHO I strongly doubt the Martens attribution as being accurate. Although Martens did so some work that has an "artistic free-form" feel to it, IMHO he did not do anything quite this loose both in terms of sloppy form and execution. The piece IMHO looks to be quite amateurish in terms of execution.... It has an "uncomfortable" look to it that I would not associate with Martens at all. (or any other quality glass house)
I know that it is also personal preference, but personally, iI think the piece is quite unattractive.... I, personally, do not think it is Martens at all and would also question if it is even Italian in origin.....
Craig