Data validation in Excel can't directly restrict data entry to specific cell references. However, you can achieve a similar outcome using a combination of data validation with a named range. Here's how:

1. Create a Named Range for Allowed Values:

- Enter the valid data options (cell references) in a separate area of your worksheet.
- Select the entire range of cells containing these references.
- Go to the "Formulas" tab.
- Click on "Define Name" in the "Defined Names" group.
- In the "New Name" box, type a clear name for this range (e.g., "AllowedReferences").
- Click "OK" to create the named range.

2. Apply Data Validation with List Option:

- Select the cell(s) where you want to restrict data entry.
- Go to the "Data" tab and click on "Data Validation" in the "Data Tools" group.
- In the "Settings" tab, under "Allow," choose "List" from the dropdown menu.
- In the "Source" box, enter an equal sign (=) followed by the name you created for your allowed references range (e.g., =AllowedReferences).
- Click "OK" to close the Data Validation window.

How it Works:

- With this setup, users can only enter values that exist within the defined named range ("AllowedReferences").
- Since this named range contains cell references, it indirectly restricts data entry to those specific cells.

Additional Considerations:

- This method assumes the allowed cell references are static and won't change frequently.
- If your allowed references change dynamically, you'll need to update the named range accordingly to maintain the restriction.
- You can also explore using custom formulas within data validation for more advanced scenarios, but it might require knowledge of formula writing in Excel.