Hi Simon,
in ADT do a "Where used"-query on your table - in your case MARA and MAKT. When you get the result you could filter it by clicking on the filter icon in the upper right corner of the view:
in SAP Gui you could directly set the filter to "DDL Sources" when hitting "Where used".
For further read:
ADT 2.31 - New version of ABAP Development Tools available now
Best regards,
Simon