So I have a C# project that generates a dll that is shared by client and server. I reference libraries like mathematics in this project. I've been referencing it from ScriptAssemblies, so I know the reference is always up to date with the package Unity is using. But Unity complains about that saying it's not able to reference the package. It eventually sorts it out as there are no compile errors. So I'm assuming the package dll's are at some point either built or copied to ScriptAssemblies during start or reload? So what is the correct way to reference packages from other projects?