A citation can only be used for novelty purposes if it clearly discloses each of the essential features of a claim.
To assess whether a citation discloses each of the essential features of a claim, it must:
"be interpreted as at the date of its publication, having regard to the relevant surrounding circumstances which then existed, and without regard to subsequent events. The patentee's claim must similarly be construed as at its own date of publication having regard to the relevant surrounding circumstances then existing. If the earlier publication, so construed, discloses the same device as the device which the patentee by his claim, so construed, asserts that he has invented, the patentee's claim has been anticipated but not otherwise."
See General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd  RPC 457 at page 485.
Note: "Date of publication" in this context should be taken to mean the date of disclosure by filing of the subject matter claimed (see Ramset Fasteners (Aust) Pty Ltd v Advanced Building Systems Pty Ltd (1996) AIPC 91-226 at 37, 322; 34 (1996) IPR 256 at 267).