diff --git a/template-parts/articles/card-article.php b/template-parts/articles/card-article.php
index 2b1ec31..fe34089 100644
--- a/template-parts/articles/card-article.php
+++ b/template-parts/articles/card-article.php
@@ -45,7 +45,7 @@ $authors = get_field('authors', $ID);
 	</div>
 
 	<div class="issue-number">
-		<?php if ($related_revue_issue_number) : ?>
+		<?php if (isset($related_revue_issue_number) && is_numeric($related_revue_issue_number)) : ?>
 			<span><?php echo $related_revue_issue_number; ?></span>
 		<?php endif; ?>
 	</div>
diff --git a/template-parts/revues/card-revue.php b/template-parts/revues/card-revue.php
index 3675dc8..f0eafe1 100644
--- a/template-parts/revues/card-revue.php
+++ b/template-parts/revues/card-revue.php
@@ -23,7 +23,7 @@ $issue_number = get_field('issue_number', $ID);
 	</div>
 
 	<div class="issue-number">
-		<?php if ($issue_number) : ?>
+		<?php if (isset($issue_number) && is_numeric($issue_number)) : ?>
 			<span><?php echo $issue_number; ?></span>
 		<?php endif; ?>
 	</div>