International Date Format

Hi
Firstly I have to say that I'm v impressed with not just Zoho Sheet, but all of the Zoho tools. I have been using USB memory stick based tools, but why transport everything on a flash drive when you can just login from anywhere?
Can anyone tell me how to format dates in the international format i.e. dd-mm-yy, as opposed to the US format mm-dd-yy?
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Cheers
Mark