diff --git a/scripts/bibSplit.pl b/scripts/bibSplit.pl
index 044a1738..c0083d6b 100755
--- a/scripts/bibSplit.pl
+++ b/scripts/bibSplit.pl
@@ -103,7 +103,9 @@ sub sanitize_text {
   
   my $urlSource = defined $obj->{url} ? $obj->{url} : '';
 
-  # Some/most/all of these *may* need sanitize_text
+  # Modified date
+  my $dateModified = defined $obj->{dateModified} ? $obj->{dateModified} : '';
+
   # optional fields - ones used vary by value of type
   my $applicationNumber = defined $obj->{applicationNumber} ? qq{"$obj->{applicationNumber}"} : '""';
   my $assignee = defined $obj->{assignee} ? qq{"$obj->{assignees}"} : '""';
@@ -185,6 +187,9 @@ sub sanitize_text {
 tags:
 url_source: $urlSource
 zotero_url: "https://www.zotero.org/groups/2914042/items/$key"
+
+# Timestamp of last modification to bibliographic item
+lastmod: $dateModified
 ---
 
 ENDITEM
diff --git a/scripts/update_bibliography.sh b/scripts/update_bibliography.sh
index 2229ae5f..e56f8f58 100755
--- a/scripts/update_bibliography.sh
+++ b/scripts/update_bibliography.sh
@@ -282,7 +282,7 @@ fi
 
 # Remove library, links, and meta objects; and some fields from entries
 # (These are not used any further on, so simplify.)
-items=$(jq 'map(del(.["library", "links", "meta", "accessed", "accessDate", "dateAdded", "dateModified"]))' <<< "$items")
+items=$(jq 'map(del(.["library", "links", "meta", "accessed", "accessDate", "dateAdded"]))' <<< "$items")
 showInfo 8 "Remove library, links, and meta objects and some unnecessary fields"
 if $debugFiles ; then
   dfn=$(debugFileName "noLibraryLinksMeta" $dfn)