 Rudel and his men built an illegal business, disguised as a haulage company, around this discrepancy in exchange rates by smuggling large sums of money from one zone to another, buying and selling currency with a profitable margin.Wolfrum states that his contact with Rudel ended in 1948 after Rudel had left for Argentina.Matthews and Foreman, authors of "Luftwaffe Aces — Biographies and Victory Claims", researched the German Federal Archives and state that Wolfrum was credited with 134 aerial victories, plus sixteen further unconfirmed claims.