Argentina air mail # C66 was issued for the Inter-America Economic Conference , OEA . Map of North and South America with the Arms of Buenos Aires . Pictorial Post Horn Cancellation Aug 16 , 1957 , Buenos Aires , Argentina , First Day of Issue . 1 stamp on 1 cacheted First Day Cover . F-VF , See Scan . $1.50 shipping & handling to a USA address / NO SHIPPING TO CHINA or GERMANY , $3.00 shipping & handling elsewhere . Combine S/H - Add 25 cents more for each additional purchase . Please view my other worldwide listings . Thank You . APS # 196666