This is the same cover reproduced in Ronald G. Shelley's catalogue The Postal History of the International Brigades in Spain 1936-39, page 127. We give his description for this piece: "Cover from Detroit to Camp de Gurs - marked "RETURN TO SENDER". This latter cover is a bit late and could be when the camp became a transit camp for Dachau and Belsen. From R Dreifus, c/o Leserman, 3401 Atkinson, Detroit, Michigan. No such name can be found in the American records - but then none of the records are fully accurate - such was the state after the war.