Hacking VoIP: Protocols, Attacks, and Countermeasures
Himanshu Dwivedi
Computer Networks
Andrew S. Tanenbaum & David Wetherall
An Introduction to the Mathematics of Financial Derivatives
Ali Hirsa & Salih N. Neftci
So long, and thanks for all the fish
Douglas Adams
The Hitchhiker's Guide to the Galaxy (4)
Gchq
Richard Aldrich