Reflection in Windows Universal Apps

I need to use the GetProperties method so I can test whether any properties in a particular class has a specified custom attribute. However it doesn't appear as though Windows Universal Apps supports this:

obj.GetType().GetProperties()

Raises the error:

'System.Type' does not contain a definition for 'GetProperties' and no extension method 'GetProperties' accepting a first argument of type 'System.Type' could be found (are you missing a using directive or an assembly reference?)

What do I need to reference in order to make use of the full reflection library?

Thanks in advance.