/r:<assembly 1>[:<assembly N>]
Forces the script engine to load assemblies referenced from a command-line explicitly.
The command above executes the test.cs script. It also instructs the script engine to load assemblies classlib1.dll and classlib2.dll at start-up.
The referenced assemblies must reside in the same directory where
the script file is or to be in the one of the CS-Script library folders
(see Using .NET assemblies for details).