HOWTO: Add a reference to Harbison and Steele

Add a reference to Harbison and Steele's C book.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/HOWTO b/Documentation/HOWTO
index 8d51c14..48123db 100644
--- a/Documentation/HOWTO
+++ b/Documentation/HOWTO
@@ -30,6 +30,7 @@
 experience, the following books are good for, if anything, reference:
  - "The C Programming Language" by Kernighan and Ritchie [Prentice Hall]
  - "Practical C Programming" by Steve Oualline [O'Reilly]
+ - "C:  A Reference Manual" by Harbison and Steele [Prentice Hall]
 
 The kernel is written using GNU C and the GNU toolchain.  While it
 adheres to the ISO C89 standard, it uses a number of extensions that are