# Single-Source Publishing Single-source publishing maintains canonical content once and projects it into multiple documents, formats, or channels. Structured authoring systems, newsroom COPE practices, and AutoSites share this source-preserving objective at different granularities. Atomic Markdown adds composition-time, sub-sentence, transformational extraction to the broader single-source model. Related: [[wiki/Create Once Publish Everywhere|Create Once, Publish Everywhere]], [[wiki/Structured Authoring and DITA|Structured Authoring and DITA]], [[wiki/Output Projection|Output Projection]], [[wiki/Atomic Markdown|Atomic Markdown]].