diff --git a/school.d/calvin.inc b/school.d/calvin.inc
--- a/school.d/calvin.inc
+++ b/school.d/calvin.inc
@@ -30,6 +30,7 @@ function calvin_info()
 				  'calvin.edu',
 				  ),
 	       'example_course_id' => 'CS-232',
+	       'registration_url' => 'https://portal.calvin.edu/Pages/WebAdvisor.aspx?title=Express+Registration&PID=ST-WERG',
 	       'student_address' => 'Knight',
 	       );
 }
diff --git a/school.d/default.inc b/school.d/default.inc
--- a/school.d/default.inc
+++ b/school.d/default.inc
@@ -77,7 +77,7 @@ function default_registration_html(Page 
   $html = ''
     . '  <p>' . PHP_EOL
     . '    Enter these codes into ' . htmlentities($school['name']) . '\'s online course registration' . PHP_EOL
-    . '    system (<a href="' . htmlentities($link_url) . '" target="_blank">' . htmlentities($link_text) . '</a>)' . PHP_EOL
+    . '    system (<a href="' . htmlentities($link_url, ENT_QUOTES) . '" target="_blank">' . htmlentities($link_text) . '</a>)' . PHP_EOL
     . '    to register for classes:' . PHP_EOL
     . '  </p>' . PHP_EOL
     . '  <ul class="synonym-list">' . PHP_EOL;