John E. Hopcroft & Rajeev Motwani 
Introduction to Automata Theory, Languages, and Computation [PDF ebook] 
Pearson New International Edition

This classic book on formal languages, automata theory, and computational complexity has been updated to present theoretical concepts in a concise and straightforward manner with the increase of hands-on, practical applications. With e Books you can: search for key concepts, words and phrases make highlights and notes as you study share your notes with friends e Books are downloaded to your computer and accessible either offline through the Bookshelf (available as a free download), available online and also via the i Pad and Android apps. Upon purchase, you’ll gain instant access to this e Book. Time limit The e Books products do not have an expiry date. You will continue to access your digital ebook products whilst you have your Bookshelf installed.