revoking users access to system tablespace?

A bit early in the new year, but here goes.

I've added a few Oracle users to my system and mistakingly gave them resource permission on the whole database. I've since given them quotas on just the user_data tablespace but how can I revoke their earlier permission.

I've tried

   revoke resource on system from ....

but it seems to have no effect. The user can still create tables in system.

It is as if that having been given global resource this overrides any local tablespace limit. I've even tried setting the resource limit to 1 K on system, but that too is overridden.

If someone tells me how, I could drop the users and re-add them, this time with just connect and then resource on user_data.

TIA (If possible please mail replies, though I will try and scan the board as  well)

	Alan Deacon (User Services)
	Central Computing Services		Email: a.deacon_at_ucl.ac.uk
	University College London		Tel: +44 71-380 7359
	Gower Street, London WC1E 6BT		Fax: +44 71-388 5406
--
	Alan Deacon (User Services)
	Central Computing Service		Email: a.deacon_at_ucl.ac.uk
	University College London		Tel: +44 71-380 7359
	Gower Street, London WC1E 6BT		Fax: +44 71-388 5406