@unpublished{repository50169,
           title = {Bukti ajar etprof 5f},
       publisher = {Universitas Muhammadiyah Prof Dr. HAMKA},
            note = {Unpublished},
             url = {http://repository.uhamka.ac.id/id/eprint/50169/},
          author = {Hamid Al Jufri, Jufri}
}