diff --git a/src/bool-array.cc b/src/bool-array.cc
index 4fc6d01..64a4fd0 100644
--- a/src/bool-array.cc
+++ b/src/bool-array.cc
@@ -20,6 +20,7 @@
    If not, write to the Free Software Foundation, Inc.,
    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 
+/* Specification. */
 #include "bool-array.h"
 
 #include <stdio.h>
diff --git a/src/hash-table.cc b/src/hash-table.cc
index 3eccc17..b6622ba 100644
--- a/src/hash-table.cc
+++ b/src/hash-table.cc
@@ -20,6 +20,7 @@
    If not, write to the Free Software Foundation, Inc.,
    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 
+/* Specification. */
 #include "hash-table.h"
 
 #include <stdio.h>
diff --git a/src/read-line.cc b/src/read-line.cc
index 1b34225..7459afe 100644
--- a/src/read-line.cc
+++ b/src/read-line.cc
@@ -21,6 +21,7 @@
    If not, write to the Free Software Foundation, Inc.,
    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 
+/* Specification. */
 #include "read-line.h"
 
 #ifndef __OPTIMIZE__