Ibid

: Often uses "Id." instead of "Ibid." as the standard abbreviation for the same purpose.

: Traditionally used, but the latest (18th) edition now discourages it in favor of shortened author-title references to avoid reader confusion. : Often uses "Id

Use "Ibid." alone if the page number is identical to the previous citation. : Often uses "Id

: You can only use it if the source you are citing is exactly the same as the one directly above it. : Often uses "Id