A method of identifying content items in a system including at least one storage device with a storage for storing content items broadcast through a broadcast system; the method including: - in the broadcast system, identifying each broadcast content item by a corresponding broadcast Content Reference Identifier (CRID); - in the storage device: - identifying each content item in the storage by a corresponding local Content Reference Identifier (CRID) identifying the content item; - storing in the storage a CRID list that includes at least for a selection of local CRIDs and broadcast CRIDs an associated validity interval including a starting date and an ending date during which interval the CRID is unique for the content item; - in response to receiving a broadcast CRID: - determining an initial validity interval for the broadcast CRID; the initial validity interval including a starting date and an ending date during which interval the broadcast CRID is unique for the associated broadcast content item; - determining whether the initial validity interval overlaps with a validity interval stored in the CRID list for an identical CRID or not; and - adding the broadcast CRID to the CRID list only if no overlap is determined. - in the broadcast system, identifying each broadcast content item by a corresponding broadcast Content Reference Identifier (CRID); - in the storage device: - identifying each content item in the storage by a corresponding local Content Reference Identifier (CRID) identifying the content item; - storing in the storage a CRID list that includes at least for a selection of local CRIDs and broadcast CRIDs an associated validity interval including a starting date and an ending date during which interval the CRID is unique for the content item; - in response to receiving a broadcast CRID: - determining an initial validity interval for the broadcast CRID; the initial validity interval including a starting date and an ending date during which interval the broadcast CRID is unique for the associated broadcast content item; - determining whether the initial validity interval overlaps with a validity interval stored in the CRID list for an identical CRID or not; and - adding the broadcast CRID to the CRID list only if no overlap is determined. - identifying each content item in the storage by a corresponding local Content Reference Identifier (CRID) identifying the content item; - storing in the storage a CRID list that includes at least for a selection of local CRIDs and broadcast CRIDs an associated validity interval including a starting date and an ending date during which interval the CRID is unique for the content item; - in response to receiving a broadcast CRID: - determining an initial validity interval for the broadcast CRID; the initial validity interval including a starting date and an ending date during which interval the broadcast CRID is unique for the associated broadcast content item; - determining whether the initial validity interval overlaps with a validity interval stored in the CRID list for an identical CRID or not; and - adding the broadcast CRID to the CRID list only if no overlap is determined. - determining an initial validity interval for the broadcast CRID; the initial validity interval including a starting date and an ending date during which interval the broadcast CRID is unique for the associated broadcast content item; - determining whether the initial validity interval overlaps with a validity interval stored in the CRID list for an identical CRID or not; and - adding the broadcast CRID to the CRID list only if no overlap is determined.