 For Overy, the problem with Mason's thesis was that it rested on the assumptions not shown by records.Overy argued that there was a difference between economic pressures induced by the problems of the Four Year Plan, and economic motives to seize foreign industry, materials and reserves of neighboring states.Meanwhile, Adam Tooze argued that from 1939 onwards, in spite of the military successes in the West, the German economy became dependent on vital imports from the East.