diff --git a/src/Views/belege/detail.php b/src/Views/belege/detail.php
index 2660bea..a482cad 100644
--- a/src/Views/belege/detail.php
+++ b/src/Views/belege/detail.php
@@ -71,6 +71,14 @@ $suppliers = $suppliers ?? [];
                 <?= $beleg['rechnungs_nr'] ? $h($beleg['rechnungs_nr']) : '<span class="text-muted">–</span>' ?>
             <?php endif; ?>
         </div>
+        <?php if (!empty($beleg['invoice_id'])): ?>
+        <div>
+            <span class="text-muted text-sm">Ausgangsrechnung</span><br>
+            <a href="/invoices/<?= (int)$beleg['invoice_id'] ?>">
+                <?= $h($beleg['rechnungs_nr'] ?? ('Rechnung #' . $beleg['invoice_id'])) ?>
+            </a>
+        </div>
+        <?php endif; ?>
         <div>
             <span class="text-muted text-sm">Brutto (Buchungen)</span><br>
             <?= $beleg['betrag_brutto'] ? '<strong>' . $fmt($beleg['betrag_brutto']) . '</strong>' : '<span class="text-muted">–</span>' ?>