Update links and add some more spec comments.
diff --git a/toys/echo.c b/toys/echo.c
index 4a3dd67..a7e6067 100644
--- a/toys/echo.c
+++ b/toys/echo.c
@@ -2,7 +2,7 @@
 /*
  * echo.c - echo supporting -n and -e.
  *
- * See http://www.opengroup.org/onlinepubs/007904975/utilities/echo.html
+ * See http://www.opengroup.org/onlinepubs/009695399/utilities/echo.html
  */
 
 #include "toys.h"
diff --git a/toys/false.c b/toys/false.c
index aa7bf0e..d4345a6 100644
--- a/toys/false.c
+++ b/toys/false.c
@@ -2,7 +2,7 @@
 /*
  * false.c - Return nonzero.
  *
- * See http://www.opengroup.org/onlinepubs/007904975/utilities/false.html
+ * See http://www.opengroup.org/onlinepubs/009695399/utilities/false.html
  */
 
 #include "toys.h"
diff --git a/toys/sleep.c b/toys/sleep.c
index 84de7ac..0c01a6e 100644
--- a/toys/sleep.c
+++ b/toys/sleep.c
@@ -2,7 +2,7 @@
 /*
  * sleep.c - Wait for a number of seconds.
  *
- * See http://www.opengroup.org/onlinepubs/007904975/utilities/sleep.html
+ * See http://www.opengroup.org/onlinepubs/009695399/utilities/sleep.html
  */
 
 #include "toys.h"
diff --git a/toys/touch.c b/toys/touch.c
index 9392967..da93ffc 100644
--- a/toys/touch.c
+++ b/toys/touch.c
@@ -4,7 +4,7 @@
  *
  * Copyright (C) 2007 Charlie Shepherd <masterdriverz@gentoo.org>
  *
- * See http://www.opengroup.org/onlinepubs/007904975/utilities/touch.html
+ * See http://www.opengroup.org/onlinepubs/009695399/utilities/touch.html
  */
 
 #define _XOPEN_SOURCE 600
diff --git a/toys/toysh.c b/toys/toysh.c
index e8fb9f1..61df13d 100644
--- a/toys/toysh.c
+++ b/toys/toysh.c
@@ -6,10 +6,13 @@
  *
  * The spec for this is at:
  * http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
- * and
- * http://www.opengroup.org/onlinepubs/007904975/utilities/sh.html
+ * and http://www.opengroup.org/onlinepubs/009695399/utilities/sh.html
  *
- * Although things like the bash man page are good to read too.
+ * There are also specs for:
+ * http://www.opengroup.org/onlinepubs/009695399/utilities/cd.html
+ * http://www.opengroup.org/onlinepubs/009695399/utilities/exit.html
+ *
+ * Things like the bash man page are good to read too.
  */
 
 // Handle embedded NUL bytes in the command line.
diff --git a/toys/true.c b/toys/true.c
index 7579642..055fb76 100644
--- a/toys/true.c
+++ b/toys/true.c
@@ -2,7 +2,7 @@
 /*
  * true.c - Return zero.
  *
- * See http://www.opengroup.org/onlinepubs/007904975/utilities/true.html
+ * See http://www.opengroup.org/onlinepubs/009695399/utilities/true.html
  */
 
 #include "toys.h"