Examples of type I duplicates (duplicates among databases).

Notes:

– All examples originated from the literatures regarding portal vein thrombosis.

– In every example, the same study was simultaneously recorded by two or three databases.

– All literatures were expressed in Vancouver reference type.

– Bold and italics formatting indicated the different styles between index and redundant paper(s).

– In every example, the reference recorded by PubMed database had more complete information.