1937 Three stampless picture postcards from a Polish volunteer in the International Brigades, each bearing boxed "S.C.C./111" ds, all three addressed to Poland, an unusual and rare usages (Image)

1938 Censored cover from a Russian volunteer in the International Brigades "132 Brigada Mista", addressed to a family member in Russia, bearing on reverse Kalinin 10c issue, very rare. (Image)