Compare sources
Two services repeating the same document are not two independent pieces of evidence. Compare the research object, data origin and period first.
Choose between two and four different sources from the list.
Access, download and API conditions depend on the service. Consult the official documentation and the resource terms.
Identify the producer of the underlying document. A portal, API and search engine may distribute the same data. To confirm a fact, seek a document with a different origin; to check a transcription, compare the original with its reuse.
The consultation date does not replace the effective, publication or acquisition date. A current and an archived result may both be correct for different periods. Record the status and version of each document.
Keep the query, name variants and filters. No result may reflect limited coverage, a delay, restrictive searching or a wrong identifier. It does not establish that a fact does not exist.
