Definition

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Materials physically and officially transferred to a repository as a unit at a single time.

The process of seeking and receiving materials from any source by transfer, donation, or purchase.

Source: https://dictionary.archivists.org/entry/acquisition.html 

Introduction

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Materials received as a unit (i.e., accession) and added to the Archives Permanent Collection. Acquisitions refers to the process of acquiring records from any source. This process results in the periodic need to reappraise (see: reappraisal)the Archives Permanent Collection for materials that need to be deaccessioned (see: deaccession).

Source: https://www2.archivists.org/glossary/terms/a/acquisition

Standards

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Acquisition is a core archival function guided by two ISO standards:

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Deaccessioning

Reappraisal

Dalhousie Libraries' Documentation

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/wiki/spaces/APM/pages/901840926

University Archives Procedure Manual - Accessioning

Further reading

Tufts University and Yale University. Ingest Guide for University Electronic Records. 2006. https://dca.lib.tufts.edu/features/nhprc/reports/ingest/index.html.