diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/client/ResourceRegistryClientImpl.java b/src/main/java/org/gcube/informationsystem/resourceregistry/client/ResourceRegistryClientImpl.java
index 547061e..05fc829 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/client/ResourceRegistryClientImpl.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/client/ResourceRegistryClientImpl.java
@@ -196,7 +196,7 @@ public class ResourceRegistryClientImpl implements ResourceRegistryClient {
 			gxHTTPStringRequest.path(type);
 			
 			Map<String,String> parameters = new HashMap<>();
-			parameters.put(AccessPath.POLYMORPHIC_PARAM, polymorphic.toString());
+			parameters.put(AccessPath._POLYMORPHIC_PARAM, polymorphic.toString());
 			gxHTTPStringRequest.queryParams(parameters);
 			
 			HttpURLConnection httpURLConnection = gxHTTPStringRequest.get();
@@ -241,7 +241,7 @@ public class ResourceRegistryClientImpl implements ResourceRegistryClient {
 			gxHTTPStringRequest.path(type);
 			
 			Map<String,String> parameters = new HashMap<>();
-			parameters.put(AccessPath.POLYMORPHIC_PARAM, polymorphic.toString());
+			parameters.put(AccessPath._POLYMORPHIC_PARAM, polymorphic.toString());
 			includeAdditionalQueryParameters(gxHTTPStringRequest, parameters);
 			
 			HttpURLConnection httpURLConnection = gxHTTPStringRequest.get();
@@ -399,8 +399,8 @@ public class ResourceRegistryClientImpl implements ResourceRegistryClient {
 			gxHTTPStringRequest.path(referenceEntityType);
 			
 			Map<String,String> parameters = new HashMap<>();
-			parameters.put(AccessPath.DIRECTION_PARAM, direction.name());
-			parameters.put(AccessPath.POLYMORPHIC_PARAM, polymorphic.toString());
+			parameters.put(AccessPath._DIRECTION_PARAM, direction.name());
+			parameters.put(AccessPath._POLYMORPHIC_PARAM, polymorphic.toString());
 			
 			if(referenceEntity == null) {
 				if(map != null && map.size() > 0) {
@@ -414,7 +414,7 @@ public class ResourceRegistryClientImpl implements ResourceRegistryClient {
 			} else {
 				logger.info("Going to get {} linked by {} to {} with UUID {}", entityType, relationType,
 						referenceEntityType, referenceEntity);
-				parameters.put(AccessPath.REFERENCE_PARAM, referenceEntity.toString());
+				parameters.put(AccessPath._REFERENCE_PARAM, referenceEntity.toString());
 			}
 			
 			includeAdditionalQueryParameters(gxHTTPStringRequest, parameters);