Articles
https://powershell.org/2012/08/powershell-workflow-when-should-you-use-it/
http://powershelldistrict.com/powershell-workflows/
https://msdn.microsoft.com/en-us/library/dd851337.aspx
https://blogs.technet.microsoft.com/heyscriptingguy/2012/12/26/powershell-workflows-the-basics/