@namespace("eu.dnetlib.iis.documentsclustering.schemas")
protocol IIS{

    record Cluster {
//      ID of the cluster
        int id;
//      pointer to parent cluster, null in case of root cluster,
//      foreign key: Cluster.id ("cluster" data store)
        union { null , int } parent = null;
//      name of cluster (possibly empty in case of all clusters except for the root cluster)
        union { null , string } name = null;
    }
    
}