Reference netstandard library from net20 app

Question

I've got a .NET 2.0 framwork console app. How do I reference a netstandard1.0 library from this one? I'm doing project.json like so

"frameworks": {
  "net20": {}
}

And getting this error

Project Reproducer is not compatible with net20 (.NETFramework,Version=v2.0). Project Reproducer supports: netstandard1.0 (.NETStandard,Version=v1.0) One or more projects are incompatible with .NETFramework,Version=v2.0.