diff --git a/abstract-specification/sections/06-other-clauses.adoc b/abstract-specification/sections/06-other-clauses.adoc
index afda7e1f..396af4b0 100644
--- a/abstract-specification/sections/06-other-clauses.adoc
+++ b/abstract-specification/sections/06-other-clauses.adoc
@@ -13,7 +13,7 @@ This Mermaid diagram should be converted to PlantUML for Metanorma, by replacing
 classDiagram
 class ReferenceSystem {
         <<abstract>>
-        dimension dimension >= 1
+        dimension "dimension >= 1"
         locationOfApplicability = 0..1
         timeOfApplicability = 0..1
         domainOfApplicability = 0..1