@unpublished{repository29185,
       publisher = {Universitas Muhammadiyah Prof.DR.HAMKA},
            note = {Unpublished},
           title = {HAKI sertifikat buku ajar IPA},
             url = {http://repository.uhamka.ac.id/id/eprint/29185/},
          author = {Zulherman, Zulherman}
}