@unpublished{repository3560,
           title = {Bahan Ajar MAtematika Diskrit},
            note = {Unpublished},
       publisher = {Universitas Muhammadiyah Prof Dr HAMKA},
             url = {http://repository.uhamka.ac.id/id/eprint/3560/},
          author = {Hikmatul Khusna, HK}
}