@ -466,6 +466,7 @@ Original Source: [Free Programming books](http://stackoverflow.com/revisions/392
* [An Introduction to Computer Networks](http://intronetworks.cs.luc.edu) (HTML, PDF, Kindle)
* [Bits, Signals, and Packets: An Introduction to Digital Communications and Networks](http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-02-introduction-to-eecs-ii-digital-communication-systems-fall-2012/readings/)
* [Code Connected vol.1](http://hintjens.wdfiles.com/local--files/main%3Afiles/cc1pe.pdf) (PDF) (book on ZeroMQ)