abstract Country = {

  cat 
    Country ; Nationality ; Language ;
  fun
    Denmark,
    England,
    Finland,
    France,
    Germany,
    Italy,
    Norway,
    Russia,
    Spain,
    Sweden 
      : Country ;
    Danish,
    English
      : Nationality ;
    DanishLang,
    EnglishLang 
      : Language ;
} ;
