Books
RHCSA & RHCE Red Hat Enterprise Linux 7: Training and Exam Preparation Guide (EX200 and EX300), Third Edition
2015
RHCSA Red Hat Enterprise Linux 8
2020
CompTIA Linux+/LPIC-1: Training and Exam Preparation Guide (Exam Codes
2017
HP-UX: HP Certification Systems Administrator, Exam HP0-A01
2008
Red Hat Certified System Administrator & Engineer
2012