1939, Argentina: Congress of the UPU, specialised collection (mnh/used/on envelope) on exhibition leaves, comprising Mi.cat.Nos.438-45A and souvenir sheets Nos.2-3 including imperforate stamps, ”Muestra” (Sample) overprints, soiv. sheets with diffarent combinations of printing plus another 14 special envelopes showing UPU thematic cancellations, on the occasion of this important congress. Very fine quality and scarce opportunistg to aquire an intact exhibition collection of this populer Argentinian issue. (M)