It sounds like you will want to explore the topic - Custom Admin Views - Create Custom Administrative Views in the Online Help. Toby Erkson has an document on using this data source as well -Server admin reports for workbooks, data connections, data sources, and their schedules
I hope that helps.
If you are using a version of Tableau Server that is less than version 10 you can use this: What's in your workbooks? The TWB Auditor v2.1
If you are using version 10 or higher of Tableau Server then use this: What's in your workbooks? The TWB Auditor
I think the TWB Auditor will be more helpful for your situation.