diff --git a/src/mods4pandas/lib.py b/src/mods4pandas/lib.py
index 0cf0407..4bf182f 100644
--- a/src/mods4pandas/lib.py
+++ b/src/mods4pandas/lib.py
@@ -269,6 +269,14 @@ class TagGroup:
         counts = {f"{xpath_expr}-count": len(values)}
         return counts
 
+    def fix_recordIdentifier_source_zdb(self) -> TagGroup:
+        for e in self.group:
+            if e.get("type") == "zdb":
+                e.attrib["source"] = "zdb"
+                del e.attrib["type"]
+                warnings.warn("Fixed recordIdentifier type 'zdb' to source")
+        return self
+
 
 def sorted_groupby(iterable, key=None):
     """
diff --git a/src/mods4pandas/mods4pandas.py b/src/mods4pandas/mods4pandas.py
index 3d71268..2d8c8c7 100755
--- a/src/mods4pandas/mods4pandas.py
+++ b/src/mods4pandas/mods4pandas.py
@@ -162,12 +162,16 @@ def mods_to_dict(mods, raise_errors=True):
                 .descend(raise_errors)
             )
         elif tag == "{http://www.loc.gov/mods/v3}recordIdentifier":
+            def no_uuid(record_identifier):
+                return record_identifier.attrib.get("type") != "uuid"
+
             # By default we assume source="gbv-ppn" mods:recordIdentifiers (= PPNs),
             # however, in mods:relatedItems, there may be source="dnb-ppns",
             # which we need to distinguish by using a separate field name.
             try:
                 value["recordIdentifier"] = (
                     TagGroup(tag, group)
+                    .filter(no_uuid)
                     .is_singleton()
                     .has_attributes({"source": "gbv-ppn"})
                     .text()
@@ -320,6 +324,10 @@ def mods_to_dict(mods, raise_errors=True):
         elif tag == "{http://www.loc.gov/mods/v3}mods":
             # XXX Ignore nested mods:mods for now (used in mods:subject)
             pass
+        elif tag == "{http://www.loc.gov/mods/v3}issuance":
+            value["issuance"] = (
+                TagGroup(tag, group).is_singleton().has_no_attributes().text()
+            )
         else:
             if raise_errors:
                 raise ValueError('Unknown tag "{}"'.format(tag))