Data-structure.md

@@ -38,7 +38,7 @@ PEP provides a number of predefined column groups and participant groups. Their
 | Name | Contains | Updates |
 | ---- | -------- | ------- |
 | `*` | All columns @@@ why does this group exist? No one should have access (except perhaps Data Administrator) @@@ | Contents are kept in sync with columns created and removed by Data Administrator. |
-| `Castor` | Columns storing data imported from the [Castor electronic data capture (EDC) system](https://www.castoredc.com/electronic-data-capture-system/). | Managed by Data Administrator. |
+| `Castor` | Columns storing data [imported](https://gitlab.pep.cs.ru.nl/pep-public/user-docs/-/wikis/Castor-integration#import) from the [Castor electronic data capture (EDC) system](https://www.castoredc.com/electronic-data-capture-system/). | Managed by Data Administrator. |
 | `CastorShortPseudonyms` | Columns storing [short pseudonyms](Data-structure#short-pseudonyms) that refer to Castor EDC records. | Automatically kept synchronized with environment configuration. |
 | `Device` | Columns storing (wearable) device registration histories. | Automatically kept synchronized with environment configuration. |
 | `ShortPseudonyms` | Columns storing [short pseudonyms](Data-structure#short-pseudonyms). | Automatically kept synchronized with environment configuration. |