How can I find a view column's base table column?

I program, administer, and support an ERP application. One of my more common tasks is to understand where data originates, finding the link between a particular report field and its data entry field in the application. To do this, I have to manually examine the DDL SQL of one or more views in order to understand the table columns, in order to match one view's table columns with another view's table columns. This manual task might require examination of four or five abstraction layers. Is there a faster way to examine the metadata to find how a view column is calculated from its base table column? Is there a way to examine Oracle's execution plan to see the rewritten query, skipping the manual inspection of the intermediate views?