Professor Henrick Hanstein, an auctioneer and art expert, provided key testimony in the case, stating that Schwitters was virtually forgotten after his death in exile in England in 1948, and that the Marlborough Gallery had been vital in ensuring the artist's place in art history.
Professor Henrik Hanstein, auktionarius og kunstekspert, var et centralt vidne i sagen ved at fremhæve at Schwitters næsten var glemt efter hans død i eksil i England 1948, og at Marlborough Gallery havde været afgørende for at sikre kunstnerens plads i kunsthistorien.