A power user's guide to OS X Server, Yosemite edition | Ars Technica
Mac OS X Server - Wikipedia
macOS Server Download: An easy to install, setup and manage application that enables you to transform your Mac running macOS into a powerful and full-featured server
macOS Server 5.12.2 Full Version Free Download - FileCR
How to get an old version of MacOS server - Macintosh How To