Git Fundamentals
Thom Parkin
Apache Solr Essentials
Andrea Gazzarini
RHSA I
Susan Lauber, Philip Sweany , Rudolf Kastl, George Hacker
Red Hat System Administration (1)
Crypto101
Laurens Van Houtven
The Book of PF: A No-Nonsense Guide to the OpenBSD Firewall
Peter N. M. Hansteen