This set of aperture cards was purchased by Australian Archives from Australian Construction Services in 1994 as microform copies of plans in A2617 because of concern about the condition of the plans, many of which were fragile and becoming damaged by high researcher use.  It was found that the set of cards included plans and drawings from a number of other series which were previously identified as separate from, but related to A2617.

The series containing the original plan could be traced back by the alphabetical prefix on the card, eg AG, AB, AC, CC etc.  The cards are grouped by area, and by project within areas.  All of the cards have numbers but they are not in any apparent order.

The areas usually, but not always, correspond to the 'block' in the Block and Section divisions of the ACT.  There are exceptions, however, and there are sub-divisions which cause confusion, for example, Acton, Acton High, Acton Drill Hall, Acton CSIRO and Acton ANU.

There are also sub-divisions within the major divisions, for example, the division 'Yarralumla - parks and gardens' also includes some cards on 'Government House' and 'Hotel Canberra' even though there is a major division titled 'Yarralumla - Government House'.  These sub-divisions do not have labels and every card needs to be examined to be certain a plan does or does not exist on a particular project.

Microform numbers on the cards relate to the number system used for plans and drawings and they relate to items contained in several series.  These numbers are not used for retrieval.  Items are retrieved by first finding the relevant area of interest and then by looking through all the cards in that area for the appropriate project.  The number will then lead to the plan or drawing number which could be part of one of 17 related series.

The 17 series are shown in the related series field of this registration even though there is no apparent common period of existence with this series. The contents date ranges of these series overlap and in fact refer to the same subject matter.  However, the CRS system only has the capacity to link series date ranges and not contents date ranges.