''Corona di Mario Diaz'' was an Italian company based in Milan, active from the mid-thirties. Unfortunately it is not known an exact date for the founding of the company, not to be confused with the same name "[[Corona]]" American and English brands. The company was active (at least by some registered trademarks) in the field of mechanical adding machines, but the only registered trademark pertaining to pens is '' CIP '' ({{Marchio|116011}}). | ''Corona di Mario Diaz'' was an Italian company based in Milan, active from the mid-thirties. Unfortunately it is not known an exact date for the founding of the company, not to be confused with the same name "[[Corona]]" American and English brands. The company was active (at least by some registered trademarks) in the field of mechanical adding machines, but the only registered trademark pertaining to pens is '' CIP '' ({{Marchio|116011}}). |