http://books.google.com/books?id=CugtAQAAIAAJ&q=shannon+theory+of+communication&dq=shannon+theory+of+communication&hl=en&ei=7PNXTrvEBYSW8QOUqam4DA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCkQ6AEwAA
The mathematical theory of communication