Can/should mcs.rsp files be used to reference my own class libraries?

I have created some .dll assemblies to be referenced by my unity scripts. What is the recommended way to include these dlls in my unity project? The documentation found here: https://docs.unity3d.com/Manual/dotnetProfileAssemblies.html

indicates that "You should reference any other class library assemblies using an mcs.rsp file" and "... Don't copy them [dlls] into the project directory."

However the example given is with a .net assembly. Does this hold true for custom assemblies that I have made myself? If so, are the steps for referencing my assemblies any different then documented for .net assemblies? If the dlls don't go into the project directory then where should they go?