1931 Mexico Newer & B/B Covers

5937- 1930, REGISTERED (2) #671 ON COVER, MONTERREY TO AUSTRIA

5927- 1922, YUCATAN (2) #2’S, LARGE MARGINS, CAMPECHE TO MERIDA, ABIERTA POR EL CENSOR LABEL

5930- 1918, CANANEA, SONORA TO NOGALES, WITH BACK STAMP, 5¢ POSTAGE DUE USED AS POSTAGE. NO BACK FLAP

5949- 1935, PORT OF CALL, GUAYMAS – U.S.S. WORDEN

5951- 1935, PORT OF CALL, LA PAZ, U.S.S. CUSHING