vba code/formula to retrieve common entries across columns

[hearthhrob4gals]

Hi,

I have for example 3 columns

Column A Column B Column C
SHEET1 SHEET2 SHEET3
SHEET2 SHEET3 SHEET4
SHEET3 SHEET4
SHEET4


I want the common entries amongst the 3 columns in a new column. The output should be

Column D
Sheet3
Sheet4


any help on this would be highly appreciated