diff --git a/src/definitions/SOL002SOL003VNFPerformanceManagement_def.yaml b/src/definitions/SOL002SOL003VNFPerformanceManagement_def.yaml
index 61fc7b1eeee361ad8e0d5d74cf6bdde1b5bf5032..4c4afa668c47e1de4217d7404778406bb7b683b1 100644
--- a/src/definitions/SOL002SOL003VNFPerformanceManagement_def.yaml
+++ b/src/definitions/SOL002SOL003VNFPerformanceManagement_def.yaml
@@ -272,10 +272,9 @@ definitions:
     properties:
       performanceMetric:
         description: >
-          This defines the types of performance metrics for the specified
-          object instances, as specified in ETSI GS NFV-IFA 027). At least one
-          of the two attributes (performance metric or group) shall be
-          present.
+          This defines the types of performance metrics for the specified object instances.
+          Valid values are specified as "Measurement Name" values in clause 7.2 of ETSI GS NFV-IFA 027.
+          At least one of the two attributes (performance metric or group) shall be present.
         type: array
         items: 
           type: string
@@ -283,7 +282,8 @@ definitions:
         description: >
           Group of performance metrics. A metric group is a pre-defined list
           of metrics, known to the producer that it can decompose to
-          individual metrics.
+          individual metrics. Valid values are specified as "Measurement Group"
+          values in clause 7.2 of ETSI GS NFV-IFA 027.
           At least one of the two attributes (performance metric or group)
           shall be present.
         type: array