@unpublished{repository27659,
            note = {Unpublished},
           title = {PERSAMAAN DIFERENSIAL 4C},
       publisher = {Universitas Muhammadiyah Prof. DR. HAMKA},
             url = {http://repository.uhamka.ac.id/id/eprint/27659/},
          author = {Tsurayya, Ayu}
}