best way to compare date, "more than one minute old"

I have a table with a DATE field called "started". What's the best way to search for rows where started is less than systime - 1 minute?

Here's what I'm using now. Is there a better way?

    select * from mytable
    where started<sysdate-(1.0/1440); -- 1440 minutes per day

Many TIA!
Mark

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Mark Harrison
Pixar Animation Studios