ASOHP. Cover of the National Museum sent to Belgium on 17/JA/1908, franked by Sc.O101 with 2 diamond-shapped punch holes, VF quality, rare! (Image)

ASOHP. Registered cover sent to Brazil on 18/FE/1920, franked by Sc.O121 + O126 (with defects), both with two star punch holes, fine quality, rare! (Image)

ASOHP. Card of the Museum of Natural History sent to ROMANIA on 12/NO/1938, with meter postage of 8c. with inscription "OFICIAL Y PRENSA", arrival handstamps, excellent quality, rare! (Image)

ASOHP. Cover of the "Arte y Cultura Popular" Association sent stampless to Argentina on 15/JUL/1940 by official mail with interesting postal markings. Back flap missing, otherwise VF! (Image)