src/Pure/Thy/sessions.scala

--- a/src/Pure/Thy/sessions.scala	Sat Nov 14 17:29:37 2020 +0100
+++ b/src/Pure/Thy/sessions.scala	Sun Nov 15 17:34:19 2020 +0100
@@ -511,7 +511,7 @@
         case s => Some(dir + Path.explode(s))
       }
 
-    def bibtex_entries: List[Text.Info[String]] =
+    lazy val bibtex_entries: List[Text.Info[String]] =
       (for {
         (document_dir, file) <- document_files.iterator
         if Bibtex.is_bibtex(file.file_name)
@@ -804,6 +804,13 @@
     def imports_requirements(ss: List[String]): List[String] = imports_graph.all_preds_rev(ss)
     def imports_topological_order: List[String] = imports_graph.topological_order
 
+    def bibtex_entries: List[(String, List[String])] =
+      build_topological_order.flatMap(name =>
+        apply(name).bibtex_entries match {
+          case Nil => None
+          case entries => Some(name -> entries.map(_.info))
+        })
+
     override def toString: String =
       imports_graph.keys_iterator.mkString("Sessions.Structure(", ", ", ")")
   }