diff --git a/docs/data-provision/aggregation/non-compatible-sources/opencitations.md b/docs/data-provision/aggregation/non-compatible-sources/opencitations.md
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--- a/docs/data-provision/aggregation/non-compatible-sources/opencitations.md
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@@ -2,3 +2,13 @@
 This section describes the aggregation workflow used to gather the citation material from OpenCitations and the relative mapping towards the OpenAIRE Graph.
 
 ## OpenCitations as an OpenAIRE Datasource
+
+[OpenCitations](https://opencitations.net/) is an independent not-for-profit infrastructure organization for open scholarship dedicated to the publication of open bibliographic and citation data. 
+OpenCitations releases datasets containing citation data as described [here](https://opencitations.net/datasets). In particular, the [COCI](https://opencitations.net/index/coci) dataset contains the DOI-to-DOI citations from Crossref.
+
+## Relation Mapping
+
+| OpenAIRE Relation Semantic | COCI csv columnrecord JSON path       | #Notes |
+|----------------------------|---------------------------------------|--------|
+| `IsCitedBy`                | `xxx`                                 |        |
+| `Cites`                    | `yyy`                                 |        |