diff --git a/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/sx/graph/SparkCreateSummaryObject.scala b/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/sx/graph/SparkCreateSummaryObject.scala
index f37abfa2a..a66da3e6d 100644
--- a/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/sx/graph/SparkCreateSummaryObject.scala
+++ b/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/sx/graph/SparkCreateSummaryObject.scala
@@ -35,7 +35,7 @@ object SparkCreateSummaryObject {
 
     val ds:Dataset[Result] = spark.read.load(s"$sourcePath/*").as[Result]
 
-    ds.repartition(6000).map(r => ScholixUtils.resultToSummary(r)).write.mode(SaveMode.Overwrite).save(targetPath)
+    ds.repartition(6000).map(r => ScholixUtils.resultToSummary(r)).filter(s => s!= null).write.mode(SaveMode.Overwrite).save(targetPath)
 
   }
 
diff --git a/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/sx/graph/scholix/ScholixUtils.scala b/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/sx/graph/scholix/ScholixUtils.scala
index ba1ebdb64..c0e28ee36 100644
--- a/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/sx/graph/scholix/ScholixUtils.scala
+++ b/dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/sx/graph/scholix/ScholixUtils.scala
@@ -1,9 +1,10 @@
 package eu.dnetlib.dhp.sx.graph.scholix
 
 import eu.dnetlib.dhp.schema.oaf.{Dataset, Result}
-import eu.dnetlib.dhp.schema.sx.summary.{SchemeValue, ScholixSummary, TypedIdentifier, Typology}
+import eu.dnetlib.dhp.schema.sx.summary.{CollectedFromType, SchemeValue, ScholixSummary, TypedIdentifier, Typology}
 
 import scala.collection.JavaConverters._
+import scala.language.postfixOps
 
 object ScholixUtils {
 
@@ -11,7 +12,13 @@ object ScholixUtils {
   def resultToSummary(r:Result):ScholixSummary = {
     val s = new ScholixSummary
     s.setId(r.getId)
-    s.setLocalIdentifier(r.getPid.asScala.map(p => new TypedIdentifier(p.getValue, p.getQualifier.getClassid)).asJava)
+    if (r.getPid == null || r.getPid.isEmpty)
+      return null
+
+    val pids:List[TypedIdentifier] = r.getPid.asScala.map(p => new TypedIdentifier(p.getValue, p.getQualifier.getClassid))(collection breakOut)
+    s.setLocalIdentifier(pids.asJava)
+
+    s.getLocalIdentifier.isEmpty
 
     if (r.isInstanceOf[Dataset])
       s.setTypology(Typology.dataset)
@@ -21,11 +28,17 @@ object ScholixUtils {
     s.setSubType(r.getInstance().get(0).getInstancetype.getClassname)
 
     if (r.getTitle!= null && r.getTitle.asScala.nonEmpty) {
-      s.setTitle(r.getTitle.asScala.map(t => t.getValue).asJava)
+      val titles:List[String] =r.getTitle.asScala.map(t => t.getValue)(collection breakOut)
+      if (titles.nonEmpty)
+        s.setTitle(titles.asJava)
+      else
+        return  null
     }
 
     if(r.getAuthor!= null && !r.getAuthor.isEmpty) {
-      s.setAuthor(r.getAuthor.asScala.map(a=> a.getFullname).asJava)
+      val authors:List[String] = r.getAuthor.asScala.map(a=> a.getFullname)(collection breakOut)
+      if (authors nonEmpty)
+        s.setAuthor(authors.asJava)
     }
     if (r.getInstance() != null) {
       val dt:List[String] = r.getInstance().asScala.filter(i => i.getDateofacceptance != null).map(i => i.getDateofacceptance.getValue)(collection.breakOut)
@@ -38,12 +51,21 @@ object ScholixUtils {
         s.setDescription(d.get.getValue)
     }
 
-    if (r.getSubject!= null && !r.getSubject.isEmpty)
-      s.setSubject(r.getSubject.asScala.map(s => new SchemeValue(s.getQualifier.getClassname, s.getValue)).asJava)
+    if (r.getSubject!= null && !r.getSubject.isEmpty) {
+      val subjects:List[SchemeValue] =r.getSubject.asScala.map(s => new SchemeValue(s.getQualifier.getClassname, s.getValue))(collection breakOut)
+      if (subjects.nonEmpty)
+        s.setSubject(subjects.asJava)
+    }
 
     if (r.getPublisher!= null)
       s.setPublisher(List(r.getPublisher.getValue).asJava)
 
+    if (r.getCollectedfrom!= null && !r.getCollectedfrom.isEmpty) {
+      val cf:List[CollectedFromType] = r.getCollectedfrom.asScala.map(c => new CollectedFromType(c.getValue, c.getKey, "complete"))(collection breakOut)
+      if (cf.nonEmpty)
+        s.setDatasources(cf.asJava)
+    }
+
     s.setRelatedDatasets(0)
     s.setRelatedPublications(0)
     s.setRelatedUnknown(0)