[Zope] Whats the Format of Date in portal_catalog( )??

Hi All, I want to get the news items by date. for eg...news items created on a particular date. I tried with container.portal_catalog(created='2003-08-13'), container.portal_catalog(created='2003/08/13') and many other.... But i am not getting anything in result...though i have some data... Is there any problem with date format...??? if yes please specify me the correct format?? Expecting your replies at the earliest bye from saravanan A A.Saravanan, WundtStrasse 7,Zi:9L1, Dresden - 01217 Germany Home: 0351-7997546 Mobile: 01797395091 ___________________________________________________ Meet your old school or college friends from 1 Million + database... Click here to reunite www.batchmates.com/rediff.asp