It is now more common to give the shortened form of previously listed reference notes, but you may want to avoid unnecessary repetition by using the Latin abbreviation ibid., short for ibidem, meaning "in the same place," for consecutive references to the same work:
Reference 2 is to the same page number. Reference 3 is to another page number of the same work.
Avoid using loc. cit. (loco citato, "in the place cited") and op. cit. (opere citato, "in the work cited") when you are making a reference to a previously cited work and when references to other documents have intervened. Tracing that earlier reference can be frustrating for readers; use of the short form of the reference note gives them the required information immediately.
© Public Works and Government Services Canada, 2014
TERMIUM Plus®, the Government of Canada's terminology and linguistic data bank
Writing Tools – The Canadian Style
A product of the Translation Bureau