diff --git a/pandoc/tar.r7rs.scm b/pandoc/tar.r7rs.scm
index 16e87e2..081d48b 100644
--- a/pandoc/tar.r7rs.scm
+++ b/pandoc/tar.r7rs.scm
@@ -95,4 +95,7 @@
     (unless (null? inputs)
       (let ((filename (string-append (number->string i) ".md")))
         (tar-write-file filename (car inputs))
-        (loop (+ i 1) (cdr inputs))))))
+        (loop (+ i 1) (cdr inputs)))))
+  (let ((nulls (make-bytevector 512 0)))
+    (write-bytevector nulls)
+    (write-bytevector nulls)))