Please see my comment to the question. The question makes no sense at all.
No, you did not add a namespace reference to a namespace. First of all, there is no such thing as "namespace reference". Second, you cannot add anything, not just reference, to a namespace. In general, a namespace does not carry any semantic at all, it simply defines how any identifier should be prefixed while naming it, nothing else.
The notion of adding references as the relationship between functional units of code written for CLR (don't mix it up with the notion of "references" as managed pointers) is the relationships between assemblies
and never anything else. Basically, one assembly can reference another assembly by its name
. If assembly does not have a strong name and not places in GAC, this involves file name. But, strictly speaking, a file name is not a name of assembly, but a name of its executable modules. In development with Visual Studio, module is almost invisible, because it allows only one kind of assembly — and assembly composed of only one, main module, but using stand-along compilers of MSBuild, it is possible to create multi-module assemblies. They are not very needed, so VS does not support them, but (at least) one module always exists.
You should start from learning the concept of assembly, a fundamental concept of .NET, CLI and CLR:
Please don't think you can do programming without good understanding of the basics. You can write something, but who would need the result of it? If you don't understand such basic things well, any development would be just a waste of time.