How Do I retrieve the source of a Text box in my Access 2007 form

Hi guys,
I have an access file (2007) with two tables, named “People” and “Sex”.
I created a query named “PeopleSex” using both tables.

I have a form, based on that query. On the form I have a text box bound to table “People”.

I need to programmatically retrieve the name of that table “People”, from the properties of the Text box.

I tried using ControlSource but didn’t succed.
Any help will be apprciated.
Aldo.