diff --git a/README.md b/README.md
index 483a26c..20ccfe1 100644
--- a/README.md
+++ b/README.md
@@ -505,7 +505,7 @@ JSON encoded body using the "application/json" content type.
 
 |Parameter|Type|Description|Required|
 |---------|----|-----------|--------|
-|guid|string|The desired guid|false|
+|guid|string|The desired guid. See OpenCDE Foundation section [1.5.1](https://github.com/buildingSMART/opencde-foundation-API#151-conflict-on-creation) when GUID already exists in target system.|false|
 |topic_type|string|The type of a topic (value from extension.xsd)|false|
 |topic_status|string|The status of a topic (value from extension.xsd)|false|
 |reference_links|array (string)|Reference links, i.e. links to referenced resources|false|
@@ -941,7 +941,7 @@ JSON encoded body using the "application/json" content type.
 
 |Parameter|Type|Description|Required|
 |---------|----|-----------|--------|
-|guid|string|The desired guid|false|
+|guid|string|The desired guid. See OpenCDE Foundation section [1.5.1](https://github.com/buildingSMART/opencde-foundation-API#151-conflict-on-creation) when GUID already exists in target system.|false|
 |comment|string|The comment text. Must not be blank or empty if provided|true, unless `viewpoint_guid` is provided|
 |viewpoint_guid|string|The GUID of the related viewpoint|true, unless `comment` is provided|
 
@@ -1175,7 +1175,7 @@ JSON encoded body using the "application/json" content type.
 
 |parameter|type|description|required|
 |---------|----|-----------|--------|
-| guid | string | The desired guid | optional |
+| guid | string | The desired guid. See OpenCDE Foundation section [1.5.1](https://github.com/buildingSMART/opencde-foundation-API#151-conflict-on-creation) when GUID already exists in target system. | optional |
 | index | integer | parameter for sorting | optional |
 | orthogonal_camera | [Orthogonal camera](#3523-orthogonal-camera) | orthogonal camera view | see viewpoint optional/mandatory fields clarification |
 | perspective_camera | [Perspective camera](#3524-perspective-camera) | perspective view of the camera |  see viewpoint optional/mandatory fields clarification |
@@ -1869,7 +1869,7 @@ JSON encoded body using the "application/json" content type.
 
 |Parameter|Type|Description|Required|
 |---------|----|-----------|--------|
-|guid|string|The desired guid|false|
+|guid|string|The desired guid. See OpenCDE Foundation section [1.5.1](https://github.com/buildingSMART/opencde-foundation-API#151-conflict-on-creation) when GUID already exists in target system.|false|
 |document_guid|string|The guid of the document (Internal document)|false|
 |url|The url (External document)|false|
 |description|string|The description of the document reference|false|