How to quote old versions of reference materials?

Citing historical editions of reference materials is both feasible and academically valid, provided the specific version consulted is clearly identified. This practice refers to referencing works in their original or earlier published forms, distinct from current or revised editions. Accurate citation requires specifying the exact edition used (e.g., "1st ed." or "2nd ed."), the original publication year, and relevant publication details like the publisher and place, which may differ from later editions. Bibliographic styles (APA, MLA, Chicago) provide specific formats for indicating edition numbers and original dates. While modern editions are typically preferred for analysis and accessibility, citing older versions remains essential when discussing the intellectual context of a particular time period, when later editions are unavailable, or when analyzing textual changes across revisions. To implement this, identify the exact edition consulted—its title page provides crucial publication data including edition statement, year, publisher, and location. Apply the relevant style guide's rules for citing editions (e.g., APA places the edition in parentheses after the title: `Title` (2nd ed.)). Briefly justify the use of the older edition, especially if significant changes exist in later versions. If citing digitized older editions, include stable access information like persistent URLs or DOIs.