diff --git a/src/main/java/org/xbib/marc/MarcField.java b/src/main/java/org/xbib/marc/MarcField.java
index 1f542f2..36b528c 100644
--- a/src/main/java/org/xbib/marc/MarcField.java
+++ b/src/main/java/org/xbib/marc/MarcField.java
@@ -20,6 +20,7 @@ import org.xbib.marc.label.RecordLabel;
 
 import java.util.Deque;
 import java.util.LinkedList;
+import java.util.List;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
@@ -533,10 +534,10 @@ public class MarcField implements Comparable<MarcField> {
 
         /**
          * A key is a compact representation of tag/indicator/value
-         * @param key
-         * @return
+         * @param key the key as string
+         * @return this builder
          */
-        public Builder key(String key, String separator, String value) {
+        public Builder key(String key, String separator, Object value) {
             String[] s = key.split(separator);
             switch (s.length) {
                 case 3: {
@@ -547,11 +548,19 @@ public class MarcField implements Comparable<MarcField> {
                     } else {
                         indicator(indicator);
                     }
-                    String subfieldId = s[2].replace('_', ' ');
-                    if (subfieldId.isEmpty()) {
-                        subfield(" ", value);
+                    String subfieldIds = s[2].replace('_', ' ');
+                    if (subfieldIds.isEmpty()) {
+                        subfield(" ", value.toString());
                     } else {
-                        subfield(subfieldId, value);
+                        if (value instanceof List) {
+                            List<Object> list = (List) value;
+                            char[] ch = subfieldIds.toCharArray();
+                            for (int i = 0; i < list.size(); i++) {
+                                subfield(ch[i]).value(list.get(i).toString());
+                            }
+                        } else {
+                            subfield(subfieldIds, value.toString());
+                        }
                     }
                     break;
                 }
@@ -563,17 +572,17 @@ public class MarcField implements Comparable<MarcField> {
                     } else {
                         indicator(indicator);
                     }
-                    value(value);
+                    value(value.toString());
                     break;
                 }
                 case 1: {
                     tag(s[0]);
-                    value(value);
+                    value(value.toString());
                     break;
                 }
                 case 0: {
                     tag(key);
-                    value(value);
+                    value(value.toString());
                     break;
                 }
                 default:
diff --git a/src/main/java/org/xbib/marc/MarcRecord.java b/src/main/java/org/xbib/marc/MarcRecord.java
index e827657..1709cb6 100644
--- a/src/main/java/org/xbib/marc/MarcRecord.java
+++ b/src/main/java/org/xbib/marc/MarcRecord.java
@@ -30,6 +30,8 @@ import java.util.Set;
 import java.util.TreeMap;
 import java.util.function.BiConsumer;
 import java.util.function.Predicate;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import java.util.regex.Pattern;
 
 /**
@@ -97,8 +99,15 @@ public class MarcRecord implements Map<String, Object> {
                                   String leaderTag,
                                   RecordLabel recordLabel) {
         MarcRecord marcRecord = new MarcRecord(map);
-        marcRecord.parseMap(map, ".", "", (key, value) ->
-                marcRecord.marcFields.add(MarcField.builder().key(key, "\\.", value.toString()).build()));
+        marcRecord.parseMap(map, ".", "", (key, value) -> {
+            if (value instanceof Collection<?>) {
+                MarcField.Builder builder = MarcField.builder().key(key);
+                ((Collection<Map.Entry<String, Object>>) value).forEach(e -> builder.subfield(e.getKey(), e.getValue().toString()));
+                marcRecord.marcFields.add(builder.build());
+            } else {
+                marcRecord.marcFields.add(MarcField.builder().key(key, "\\.", value.toString()).build());
+            }
+        });
         if (map.containsKey(formatTag)) {
             marcRecord.format = map.get(formatTag).toString();
         }
@@ -350,19 +359,23 @@ public class MarcRecord implements Map<String, Object> {
     }
 
     @SuppressWarnings("unchecked")
-    private void parseMap(Map<String, Object> source, String separator, String prefix, BiConsumer<String, Object> consumer) {
+    private void parseMap(Map<String, Object> source, String separator, String prefix,
+                          BiConsumer<String, Object> consumer) {
         source.forEach((k, v) -> {
             if (v instanceof Map) {
                 parseMap((Map<String, Object>) v, separator, prefix + k + separator, consumer);
             } else if (v instanceof Collection) {
                 Collection<Object> collection = (Collection<Object>) v;
+                List<Map.Entry<String, Object>> list = new LinkedList<>();
                 for (Object object : collection) {
                     if (object instanceof Map) {
-                        parseMap((Map<String, Object>) object, separator, prefix + k + separator, consumer);
+                        parseMap((Map<String, Object>) object, separator, prefix + k + separator, (a,b) -> list.add(Map.entry(a,b)));
                     } else {
-                        consumer.accept(prefix + k, object);
+                        list.add(Map.entry(prefix + k, object));
                     }
                 }
+                Logger.getLogger("").log(Level.INFO, "list = " + list);
+                consumer.accept(prefix + k, list);
             } else {
                 consumer.accept(prefix + k, v);
             }
diff --git a/src/test/java/org/xbib/marc/MarcRecordTest.java b/src/test/java/org/xbib/marc/MarcRecordTest.java
index cab9f9f..b5749cd 100644
--- a/src/test/java/org/xbib/marc/MarcRecordTest.java
+++ b/src/test/java/org/xbib/marc/MarcRecordTest.java
@@ -36,6 +36,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import java.util.regex.Pattern;
 
 public class MarcRecordTest {
@@ -216,6 +218,18 @@ public class MarcRecordTest {
         assertEquals("Hello World", marcRecord.getFields().stream().filter(m -> m.getTag().equals("100")).findFirst().get().getFirstSubfieldValue("a"));
     }
 
+    @Test
+    public void testMarcRecordFromMapNested() {
+        Map<String, Object> map = Map.of("016", Map.of("7_", List.of(Map.of("2", "DE-101", "a", "010000151"), Map.of("2", "DE-600", "a", "23-1"))));
+        MarcRecord marcRecord = MarcRecord.from(map);
+        Logger.getLogger("").log(Level.INFO, "marcrecord = " + marcRecord);
+        Logger.getLogger("").log(Level.INFO, "marcrecord fields = " + marcRecord.getFields());
+        marcRecord.filter(f -> "016".equals(f.getTag()), f-> {
+                    Logger.getLogger("").log(Level.INFO, "f = " + f);
+        });
+    }
+
+
     @Test
     public void testMarcRecordFromMapAsMap() throws IOException {
         Map<String, Object> map = new TreeMap<>(Map.of("001", "123",