diff --git a/pom.xml b/pom.xml
index 4b499a8..5e5131c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -32,7 +32,7 @@
         <connection>scm:git:gitea@code-repo.d4science.org:D-Net/dhp-schemas.git</connection>
         <developerConnection>scm:git:gitea@code-repo.d4science.org:D-Net/dhp-schemas.git</developerConnection>
         <url>https://code-repo.d4science.org/D-Net/dhp-schemas/</url>
-        <tag>dhp-schemas-2.9.23</tag>
+        <tag>dhp-schemas-2.9.24</tag>
     </scm>
 
     <description>This module contains common schema classes meant to be used across the dnet-hadoop submodules</description>
diff --git a/src/main/java/eu/dnetlib/dhp/schema/common/ModelSupport.java b/src/main/java/eu/dnetlib/dhp/schema/common/ModelSupport.java
index bf0eed1..1aa0d8f 100644
--- a/src/main/java/eu/dnetlib/dhp/schema/common/ModelSupport.java
+++ b/src/main/java/eu/dnetlib/dhp/schema/common/ModelSupport.java
@@ -158,6 +158,21 @@ public class ModelSupport {
 		}
 	}
 
+	/**
+	 * Helper method: lookup relation inverse, given the direct relation encoding (case insensitive)
+	 * @param encoding
+	 * @return the relation inverse descriptor, throws @IllegalArgumentException when not found.
+	 */
+	public static RelationInverse findInverse(String encoding) {
+		return ModelSupport.relationInverseMap
+				.entrySet()
+				.stream()
+				.filter(r -> encoding.equalsIgnoreCase(r.getKey()))
+				.findFirst()
+				.map(r -> r.getValue())
+				.orElseThrow(() -> new IllegalArgumentException("invalid relationship: " + encoding));
+	}
+
 	/**
 	 * Helper method: fina a relation filtering by a relation name
  	 * @param relationName
@@ -181,7 +196,7 @@ public class ModelSupport {
 	 * @return
 	 */
 	public static String rel(String relType, String subRelType, String relClass) {
-		return String.format("%s-%s-%s", relType, subRelType, relClass);
+		return String.format("%s_%s_%s", relType, subRelType, relClass);
 	}
 
 	private static final String schemeTemplate = "dnet:%s_%s_relations";