The PowerShell Scripting and Toolmaking Book
Don Jones & Jeffery Hicks
Beginning Power Apps
Tim Leung
MediaWiki (Wikipedia and Beyond)
Daniel J. Barrett
systemd for Linux SysAdmins: All You Need to Know About the ...
David Both
Using and Administering Linux: Volume 2: Advanced Topics
Using and Administering Linux (2)
Using and Administering Linux: Volume 1: Getting Started
Using and Administering Linux (1)
Using and Administering Linux: Volume 3: Network Services
Using and Administering Linux (3)