In bibliographies and footnotes, researchers often use the abbreviation 'ibid', which means

The abbreviation ibid stands for ibidem, meaning in the same place.

It refers the reader to the source cited immediately before, avoiding repetition.

Introduction is not the meaning of ibid at all.

And the following is the sense of the abbreviation ff., not ibid.

Here and there does not correspond to any standard citation abbreviation.

When the page differs, ibid is followed by the new page number.