Git Pocket Guide
Richard E. Silverman
PostgreSQL: Up and Running
Regina O. Obe & Leo S. Hsu
Mastering Apache Spark
Mike Frampton
TCP/IP Illustrated: Volume 2 The Implementation
W. Richard Stevens & Gary R. Wright
TCP/IP Ilustrated (2)
The Book of PF: A No-Nonsense Guide to the OpenBSD Firewall
Peter N. M. Hansteen