ibid.

Ibid. (Latin, short for ibidem, meaning "in the same place") is the term used to provide an endnote or footnote citation or reference for a source that was cited in the preceding endnote or footnote. This is similar in meaning to idem (meaning something that has been mentioned previously; the same), abbreviated Id., which is commonly used in legal citation. To find the ibid. source, one must look at the reference preceding it.