diff --git a/li.strolch.model/src/main/java/li/strolch/model/Resource.java b/li.strolch.model/src/main/java/li/strolch/model/Resource.java
index 9495ac23f..6caea54df 100644
--- a/li.strolch.model/src/main/java/li/strolch/model/Resource.java
+++ b/li.strolch.model/src/main/java/li/strolch/model/Resource.java
@@ -96,7 +96,7 @@ public class Resource extends AbstractStrolchRootElement implements StrolchRootE
 	}
 
 	@SuppressWarnings({ "unchecked" })
-	public <T extends StrolchTimedState<?>> T getTimedState(String id) {
+	public <T extends StrolchTimedState<? extends IValue<?>>> T getTimedState(String id) {
 		if (this.timedStateMap == null) {
 			return null;
 		}