This problem appears as problem GT18 in Garey and Johnson's classical book on NP-completeness, and is a rather straightforward reformulation of another decision problem on families of finite sets.
Ovaj problem se javlja kao problem GT18 u knjizi Gerija i Džonsona o NP-kompletnosti, i dosta je direktna reformulacija drugog problema rešavanja porodice ograničenog skupa.