diff --git a/src/Components/Inlines/Link.php b/src/Components/Inlines/Link.php
index e6a4c99..41780c6 100644
--- a/src/Components/Inlines/Link.php
+++ b/src/Components/Inlines/Link.php
@@ -79,6 +79,8 @@ final class Link implements Inline
                 $definition = \strtolower($label);
             }
 
+            $definition = \preg_replace('/\s++/', ' ', \trim($definition));
+
             $data = $State->get(DefinitionBook::class)->lookup($definition);
 
             if (! isset($data)) {
diff --git a/tests/data/text_reference.html b/tests/data/text_reference.html
index 11e4d37..3d7b854 100644
--- a/tests/data/text_reference.html
+++ b/tests/data/text_reference.html
@@ -5,4 +5,8 @@
 one</a> defined on 2 lines</p>
 <p><a href="http://example.com">one</a> with a mixed case label and an upper case definition</p>
 <p><a href="http://example.com">one</a> with the a label on the next line</p>
-<p><a href="http://example.com"><code>link</code></a></p>
\ No newline at end of file
+<p><a href="http://example.com"><code>link</code></a></p>
+<p>This one has a <a href="/foo">line
+break</a>.</p>
+<p>This one has a <a href="/foo">line
+break</a> with a line-ending space.</p>
\ No newline at end of file
diff --git a/tests/data/text_reference.md b/tests/data/text_reference.md
index 1a66a5c..74b8dae 100644
--- a/tests/data/text_reference.md
+++ b/tests/data/text_reference.md
@@ -18,4 +18,12 @@ one][website] defined on 2 lines
 [one]
 [1] with the a label on the next line
 
-[`link`][website]
\ No newline at end of file
+[`link`][website]
+
+This one has a [line
+break].
+
+This one has a [line
+break] with a line-ending space.
+
+[line break]: /foo
\ No newline at end of file