Queries :: Identify Duplicates With Three Criteria

I have the following columns in my table 'Catalogue'.

Contract_contractitem
contract
Supplier name
Item number
Short description
Long description

I need to identify duplicates if the short desciption is the same, long desciption is the same but the item number is NOT the same.

e.g.

4700000551_978, 4700000551, FISHER SCIENTIFIC BIOTECH LINE ApS, mbp-6014, 0,2 ml PCR Tube, Hotstart, wax bead, NS, 0,2 ml PCR Tube, Hotstart, wax bead, NS 96 tubes/pack, 10 packs/Cs

4700000551_977, 4700000551, FISHER SCIENTIFIC BIOTECH LINE ApS, mbp-6010, 0,2 ml PCR Tube, Hotstart, wax bead, NS, 0,2 ml PCR Tube, Hotstart, wax bead, NS 96 tubes/pack, 10 packs/Cs